Star Trek: Every Two-Parter Ranked From WORST To BEST

First on the list, Star Trek: Discovery's third season two-parter is on shakier ground than its title. Terra Firma, Parts 1 & 2 weren't outright bad by any means, but there are 41 double episodes that are better. Life, the Mirror Universe, and Everything, and one in the form of Carl, Guardian of Forever, or it was curtains for Philippa Georgiou.

At the time, Terra Firma was meant as the backdoor (and the big gate) to the ex-Emperor's own spin-off TV show. That was a rocky road to what was Star Trek's first-to-streaming movie. The two-parter's most egregious error was, then, no doubt, that it became 'three-' in what was made of Star Trek: Section 31.

Birthright, Parts I & II are fairly forgettable episodes, especially given the competition in the sixth season of Star Trek: The Next Generation. At times, they both border on the tedious. It's not like the Enterprise-D stopped by Deep Space 9 every other Tuesday. Here, there was barely any point that it did, save to get Julian on board.

Most of the two-parter — which really didn't need to be one — was spent in Data's dreams, and then in Worf's 'what Klingon warriors worry about'. Over on Star Trek: Deep Space Nine, they were filming Move Along Home at the same time. It might somehow be preferable just to watch that twice instead!

More Latin is not another copy-and-paste job. In fact, 'Et in Arcadia Ego' is a reminder that, even in paradise, death is ever-present. For Star Trek: Picard's season one finale, the Romulan doomsday of 'Ganmadan' failed to repeat itself. The end of the world (or galaxy) was just the end of Jean-Luc, and the ego death of (a) Data, however fleeting.

The greatest strength of this two-parter is the otherworldly reunion between former captain and former lieutenant commander before Picard 2.0. You'd have to have turned off your emotion chip not to be moved by that. The two-parter's greatest weakness was the self-same duplication, not in ego, but in ships in orbit.

'Sacrificing' Captain Picard as merely another pawn in the illicit affairs of the galaxy was a bold move. Naturally, he was never dead in the first place.

The rest of the two-parter wasn't quite as sound, though it was still a lot of fun. The bad guy was as weak as his method of coercion. The bad girl — played by none other than Robin Curtis — was far more entertaining than the 'Stone of Gol' she sought.

That device — a 'psionic resonator' from ancient Vulcan, before the 'Time of Awakening' — was also as odd as Gambit's freeze-frame cliffhanger, the poor man's, The Best of Both Worlds. This was the final season of Star Trek: The Next Generation. Its fourth and fifth episodes could and should have been a lot better. Then again, they could have been Masks.

Yes, we know! We said we weren't doing pilot episodes. In this case, like Michael Burnham, we'll just have to break the rules. Get ready to have your nerves pinched!

The streaming era did things differently from the outset — no main ship, no more Captain Georgiou, and for one, no more Starfleet career (for a bit). The Vulcan Hello and Battle at the Binary Stars weren't the typical treatise for a new series, but, in many respects, more like a classic two-parter with a relatively self-contained plot and a cliffhanger. There was no 'To Be Continued…,' but then, we're still feeling mutinous.

All things considered, this was a solid start for Star Trek: Discovery — a visual feast combined with captivating intrigue. Sadly, we just still haven't recovered from the shock of those Klingons!

As a time traveller, Daniels sure did pick his moments. Just when the crew of the NX-01 thought they were safe after a season-long survival epic, they found themselves flung into another existential crisis for all of time in an alternate 1944. If you thought the Sphere Builders were bad, wait until you've met the "holy mother of…" Na'kuhl!

Storm Front and Storm Front, Part II is a thrilling two-parter that would rank higher on this list, but for its own untimely placement at the start of Star Trek: Enterprise's fourth season, and its rush to wrap up the Temporal Cold War. Like the crew, we, the audience, needed to breathe a little after the Xindi arc.

Over the years, Unimatrix Zero has taken more fire than the tactical cube within it. Is it really that bad? No. Is it great? No. Its cliffhanger is also far better than it gets credit. Done and overdone with the Borg, perhaps, but Janeway, Tuvok, and B'Elanna all assimilated? Come on! That was still pretty shocking. Of course, the real cliffhanger was that unrealised rendezvous with Harry.

Unimatrix Zero's greatest strength was also its greatest weakness. The very idea of a resistance movement within the Borg collective unconscious was a good one. Its execution was lacklustre. The romantic relationship at its core failed to convince. Banished to the backends of the Beta Quadrant, Mr Axum was never spoken of again.

The first of the animated entries on this list was the first to use 'To Be Continued…' since the Star Trek: Enterprise episode Demons (see later on this list). It was also the first time — we assume — that Captain Freeman had been arrested, and accidentally perp-walked, in front of her crew, providing for quite the jaw-dropping cliffhanger to the second season of Star Trek: Lower Decks.

First First Contact ended on an emotional beat. Grounded picked up to pure comedy chaos as various screens (and potted plants) were turned off Beckett Mariner style, all with a view of the 'impractical' Golden Gate Bridge. The episode then did the smorgasbord of Earth hotspots and self-references — from ketracel-white hot gumbo at Sisko's Creole Kitchen to churros in Bozeman and raisins in Modesto.

Star Trek: Discovery's second season impressed enough that fans demanded a spin-off by way of petition. Before Pike, Spock, and Una could get their own, the Discovery had to be sent off to the 32nd century, and never spoken of again in the 23rd (onwards) under penalty of treason.

If it's a space battle you desire (and why wouldn't you?), a space battle you shall get. 'The Battle Near Xahea' in Such Sweet Sorrow, Part 2 still ranks as one of the best put to Trek, barely skipping a dramatic beat. The mid-point arrival of Po, the Klingons, and sister Siranna was the touch that sealed the deal.

All in all, Such Sweet Sorrow is a visually stunning two-parter, which would have placed higher on this list, but for a few liberties and liabilities with the plot. The unfortunate fact is that Discovery's spore drive was more science fantasy than science fiction, and a canonical contortion, in the first place. Its use did eventually grow on us, not unlike one of its mushrooms. Its non-use for over 900 years was always a fudge though.

How spoiled do you have to be to demand more from a world in which everything is already free? The answer to that question is measured in 'Nick Locarnos'. Dead ringer or not, Locarno was no Tom Paris, barely even a Lieutenant Marseille. He proved that much in the two-part season four finale of Star Trek: Lower Decks.

In fact, only Lower Decks could bring back an obscure, but ultimately memorable, character as the 'big bad' of the season at the end of an episode that owes its pun to another. The Locarno cliffhanger will hold up as one of the most shocking of all time.

Old Friends, New Planets was just as strong. Nova Squadron got a self-promotion to Nova Fleet, and we got to see more through flashbacks of the events surrounding The First Duty. Boimler in command knocked it out the park, and smashed it into the shield grid. And let there be latinum, or it's Genesis for you!

At the start of Star Trek: Prodigy's first season, the kids had risked it all to escape their prison on Tars Lamora. Now, in the mid-season two-parter, they dared to return with a plan to save the rest of the "Unwanted" from the dastardly Diviner and his Drednok.

A Moral Star, Parts 1 & 2 do in about 40 minutes what other two-part episodes have failed to do in twice that time. The premise is established with astounding proficiency, leaving way for the action, delicately intertwined with moments of genuine pathos and laugh-out-loud comedy.

A Moral Star, Part 2 ended on a dramatic cliffhanger — a future doomsday for Starfleet — and saw the return of Vice Admiral Janeway, last seen in Star Trek: Nemesis. The end of A Moral Star, Part 2 also marked a particularly long pause for answers between Parts 1 and 2 of the season itself — from the beginning of February 2022 to nearly the end of October that same year.

First day on the new job? Try not to trigger a core overload! This whole place runs on tylium, but there are no Cylon second chances. Workplace alienation and the (ill-)treatment of the immigrant labour force is the theme — one that sadly hits home more today than it did when the two-parter was first broadcast. In that, Workforce is a fine piece of science fiction, even if it doesn't quite reach the dizzying heights of the other Star Trek: Voyager two-parters.

Allegories and memory manipulations aside, Workforce and Workforce, Part II were the chance for a 'what if' for the crew of Voyager. So close to the series finale, 'what if they ended up settling in the Delta Quadrant'? The 'what if' of the Emergency Command Hologram (ECH) also went from daydreams to reality for the Doctor. In actuality, Captain Janeway was no fool for the falsely implanted premises of another life: "Not for a second."

"Disguise fair nature with hard-favour'd rage," declared Shakespeare's Henry V in the "Once more unto the breach…" speech. In less elegant terms, we were all bloody p*ssed off in June 2023 when we heard the news that Star Trek: Prodigy had been cancelled mid-post-production of season two. Its opener, Into the Breach, is the two-parter of several that was nearly never seen… but for the warlike Michele Stokes herself and her plane.

With the move to Netflix (and also France.tv), Prodigy's second season became the first in Star Trek history to be released all at once. Nothing is a two-parter longer than it takes to hit 'next episode,' or to wait for the autoplay, but moving the goalposts doesn’t mean we have to switch to a different game.

Into the Breach, Parts I & II thoroughly deserve their place on this list. They saw the return of the Doctor, introduced us to the glorious Voyager-A, and, best of all, they began on the always marvellous Murf.

There is nothing basic about Basics — the first of several two-parters in Star Trek: Voyager's run home. For a moment, it looked like the crew would be living out (or dying out) the rest of their days on Planet Pliocene, forever sprinting away from the locals.

Of course, the cliffhanger was never 'Are they going to make it?' but 'How are they going to make it?' back to the ship. Tom Paris, the Talaxians, a hologram, and a repentant murderer, that's how! That was one hell of a plan to have come up with in one hour, Tommy boy!

Stripped down to the essentials, the plot is not dissimilar to that of Workforce and Workforce, Part II — rescue from an alien world. If the Basics two-parter places higher on this list, then it's because, so early on, the stakes were extra cataclysmic. And, at the time, you had to wait the summer to see Voyager fly back through the atmosphere.

The Maquis two-parter is far from perfect. Its first half drags somewhat towards a cliffhanger that could arguably be seen coming a few light-years away. Moreover, since we, the audience, had only just met Commander Calvin Hudson, it was difficult to be all that invested in his change of allegiance.

The Maquis, Parts I & II ultimately stand out for their importance to Star Trek lore. Prefigured in the Star Trek: The Next Generation episode Journey's End, this was the formal introduction of the titular rebels, named after those groups of the French and Belgian Resistance during the Second World War.

The movement would continue to make its presence felt on Star Trek: Deep Space Nine, The Next Generation, and Voyager. The Badlands also got their first mention in The Maquis, Part I. As Sisko pointed out, "a few ships have been lost there over the past year or two".

Trying to find satisfying in-universe explanations for out-of-universe issues is like trying to find the haystack in the needle — we're imagining the 'problem' the wrong way round. Those sudden forehead ridges probably did need some sort of internally consistent clarification. Affliction and Divergence gave us one. If we didn't like the answer, we probably should have asked better questions!

This fourth season Star Trek: Enterprise two-parter provided one of the most gripping cliffhangers and resolutions of the franchise. No bomb on the bus — a subroutine in the warp matrix instead. Sabotaged by the Klingon Augments, the NX-01 couldn't go below warp 5 or the reactor would breach.

Luckily, the NX-02 was nearby. Now, they just had to zipwire Mr Tucker across to perform one of the biggest 'have you tried turning it off and on again?' jobs in history. Oh, and Malcolm's been a very naughty boy!

Demons and Terra Prime often pull double duty for many fans as a strong two-parter in their own right and as Star Trek: Enterprise's unofficial series finale. 

Both episodes represent what was best about Enterprise. As a series, it had the tough task of being the OG prequel, but set far enough back so as not to risk overlap with familiar faces. Seeing humanity's first forays into deep space and the interstellar community, on the road to the Federation, was always a tantalising prospect.

The Temporal Cold War, and time travel more widely, meant that Enterprise was never truly isolated from the future of the franchise. It was the resurgent xenophobia in the wake of the (temporally influenced) Xindi attacks that emboldened the likes of Paxton in Demons and Terra Prime. 

Borg behind the door, we've played Data/Lore before. Descent is a thoroughly decent two-parter, even if legacy has made its reveal part of a tad bit of franchise repetition. The first half, the first scene, will, of course, be forever iconic for the best of cameos — that of the late Professor Stephen Hawking.

With no disrespect to Brent Spiner's always excellent double act, Descent's most intriguing aspect, developed in the second half, was the continuation of Hugh's story after I, Borg. Individuality was more of a sickness for the Collective than any invasive computer program could be. In Descent, Part II, Doctor Crusher also got to show off her aptitude for command, and not without a little in-joke about metaphasic shields.

Perhaps all the world is a holodeck under the thumb of a Hirogen, in which we're just fighting for our lives. Somewhat reduced in scale, that was the deadly dilemma faced by those Voyager crewmembers not locked in their quarters (or working on the bridge) in The Killing Game.

The Hunters have caught up. We don't see the battle, but we know who won. The r/Resistance now plays out on Holodeck One as much as it does on the rest of the ship. Kathryn is Katrine, leader of, in essence, a Maquis cell. Chakotay is the American liberator of 'Sainte Claire'. The cliffhanger was certainly dramatic — a massive explosion and half of Voyager now one unending set of simulations.

In the US, The Killing Game and The Killing Game, Part II were also originally aired on the same night — a first for a Star Trek two-parter (not including feature lengths). In fact, The Killing Game was promoted as a feature-length single episode, but for reasons unknown even to the Star Trek: Voyager producers, was shown as two separate episodes.

A leads to B leads to… one damn good two-parter. Time travel's not just for headaches, after all. Future's End and Future's End, Part II gave us many things — "freakosaurus," Blaine's twin brother, and the Doctor's mobile emitter. Both episodes also provided the perfect opportunity to see the crew of Voyager home before they were home — "Right place, wrong time". As for the nefarious billionaire, well, times never change!

As a two-parter, Future's End is an extended attempt at social commentary — on the disparity between the 'haves' and the 'have-nots' — but remains eminently aware of its own farcical premise throughout. It works by blending the lighter-hearted with the more dramatic, and, at times, the overtly pedagogic. Its villain, Henry Starling, might be moustache-twirlingly one-note, but then, what use is character development when a photon torpedo will do?

At times camper than Christmas in the Nexus, the Time's Arrow two-parter is never winning awards for subtlety of any sort. That is largely its charm. I say, I say, I dare say, it has been parodied to perfection, too. Get your best cosplay on. Sometimes the Twain shall meet!

The premise was relatively simple: some rando in a silver jumpsuit finds Data's head buried in a cavern beneath San Francisco and shows it to Data (who still has a head) and Captain Picard. Standard! In practice, things were rather more complicated.

To dismantle and rebuild Data, Time's Arrow and Time's Arrow, Part II took a mind-boggling bend to the 19th century and back via Guinan, Samuel Clemens, and the neural energy-sucking Devidians. This was pure sci-fi fun!

The past of Past Tense has caught up with us. The Bell Riots were last year. Star Trek: Deep Space Nine's third season two-parter was as much a bold allegory of homelessness in mid-'90s America as it was a projection towards the future should things continue along the same path.

That Past Tense, Parts I & II don’t feature higher on this list is because they are, at times, a little ham-fisted in their social commentary, most notably in the dialogue between the more historically savvy Sisko and the less well-apprised Bashir. Often, he states what we are meant to feel.

It was also always a bit of a cheat to return to 'great man' and 'big events' theory as the true impetus for social and historical change. In reality, only the tireless work at a grassroots level, not a singular occurrence stamped in time, will make the 21st century a safer place for all to live in across the globe. To think otherwise is to let oneself off the hook.

In theory, The Search is a three-, not a two-, parter, because, in practice, the Jem'Hadar don't like campers. In reality, Star Trek: Deep Space Nine's second season finale was relatively self-contained. Its conclusion did come with an ominous warning, the response to which was decloaked in the opener to The Search, Part I.

If you go looking for trouble, you'll probably find it in the Omarion Nebula. Though, to put it in playground terms, the Dominion and its Founders, well, they started it! Big reveal: Odo's people and the overlords of the Gamma Quadrant were one and the same. You had to wait until practically the end of Part II to find that out. Until then, "Welcome home!" Please enjoy our complementary tour of the arboretum!

Seasons one and two of Star Trek: Enterprise are far better than their reputation would suggest. We only have to look to the episodes that straddle them to see that. It all started with a massive explosion, followed by incomprehension, and time travel. Shockwave, and Shockwave, Part II were high-end sci-fi, with a vertiginous cliffhanger, and clever resolution.

Before Kovich was Kovich, he was Daniels, plucking Captain Archer every which way out of the timeline. At first, in Shockwave, that merely meant more room for a chat, semi-clothed, about quantum beacons and data discs. Second, it caused the end of everything on Earth in, and at some point before, the 31st century. It was a long way down what was left of that skyscraper!

In Part II, we also learnt that, in the regular 31st century, they taught teenagers how to communicate through time. Prank calls must have been something else! Thankfully, this particular one saved the past and its future.

Truth be told, Ascension, Parts I & II were contenders for higher up on this list. But with so many outstanding outings from Star Trek: Prodigy, choices had to be made. Like the rest of season two, neither episode leaves much more than nitpicking to reproach it with. Both deftly mix action, emotion, temporal physics, and high villainy. They even got a Morn joke in there, too!

Asencia was on the rise, and taking no prisoners, except one. The Rev-1 was a warship, packed with temporal technology, but ultimately no match for the combined forces of Voyager, the Protostar, and the new Nova Squadron, done the right way. (Boothby Supernova in the sky…) In all of that, Zero's gut-wrenching self-sacrifice to stop the incursor weapon couldn't fail to reduce us to tears.

Before all else, In a Mirror, Darkly deserves credit for daring to do. No other Star Trek had set an episode (let alone two) entirely from the perspective of another universe. Even the title credits were terrifyingly Terran! The opener was 'First Contact'… with a shotgun! In showrunner Manny Coto's words on the DVD extra Inside the Mirror Episodes, this was a "pure romp".

Like all episodes in the mirror universe, the In a Mirror, Darkly two-parter is hammier than non-replicated ham. More than anything, that is a compliment. It takes a great deal of subtlety to be so successfully extravagant. The inclusion of the USS Defiant as a focal plot point was a stroke of genius, requiring the elaborate reconstruction of numerous Constitution-class sets — the most (at that point) since The Original Series.

It is more than fitting that the two-part finale of Star Trek: Prodigy's first season should be named after Supernovae. From the beginning, the show managed a dazzling feat, creating the new, the fresh, the exciting, out of, and alongside, the utmost respect for the old. It also had a protostar at its core.

In terms of pure explosions, Supernova, Parts 1 & 2 were not lacking either. Seen briefly at the end of Mindwalk, a whole armada of Starfleet ships, including the USS Defiant, the USS Thunderchild, the USS Centaur, and the USS Sovereign, took an infernal beating to the whim of the Vau N'Akat Construct. Speaking of 'beatings,' shout out to one kick-arse, raspberry-blowing, butt-slapping, Murf!

We also commend the show's promotion of language learning as a means of bringing people together. As the extraordinary polyglot Gwyn herself put it:

Because in the infinite of space, everyone needs to know there is a place out there willing to accept us all no matter how different we think we are.

If that's not Star Trek in one sentence, nothing else is!

If there is to be no more Star Trek: Prodigy, then at least, like the snake and its own tail, it ended as it meant to go on. There have been few better series finales. Ouroboros, Parts I & II were the conclusion to the near-perfect second season — both an ingenious return, full circle, to the very beginning of season one, and a new, hopeful course for the future, set aboard the USS Prodigy. We sincerely hope to see ship and crew again.

After wrestling with Asencia's forces and wrapping up the Loom, Wesley returned to see his Mum and brother, Admiral Janeway took her much-deserved retirement, and the kids returned to the Academy. Ouroboros, Part II had one last twist in the tale, however — the synth attack on Mars and its fallout. Never underestimate a so-called 'kids show'!

Instead of the lights, just show him the memes! There are definitely more than four of those. The enduring power of the Chain of Command two-parter lies in its endless repeatability — largely removed from the message, but all in good fun (especially for the Internet). Loathe him or loathe him just a little bit less, Chain of Command also gave us the equally iconic Captain, now Admiral, Jellico.

Put two of the finest Shakespearean actors, preferably well lit, alone in a room together, you're going to get some ACTING!

Patrick Stewart gave a harrowing performance as the victim of physical and psychological torture. Both he and writer Frank Abatemarco had consulted with Amnesty International on the scenes.

For Chain of Command, David Warner was whisked in to play opposite his old friend with only three days' warning before filming began. He didn't even have time to learn his lines for Gul Madred. Though you would never know it, he read mostly from cue cards instead.

Doctor Bashir wasn't in prison for an infraction of the Starfleet uniform code, but he was still operating under previous dress regulations when he popped up in Jem'Hadar jail in In Purgatory's Shadow - and that wasn't even the cliffhanger! 

No need for sandwiches, there is so much plot and character development in In Purgatory's Shadow and By Inferno's Light, you'll be satiated for weeks. Full-scale war would have to wait until Call to Arms. For the moment, Cardassia had joined the Dominion, and Dukat was now head of the Cardassian 'government' (obviously!).

We learnt that Enabran Tain was Garak's father, that Breen don't have blood, and that you should only go to warp inside a solar system if that solar system is about to be reduced to cinders.

Star Trek: Deep Space Nine made a point to point out that, even in the idyll of the 24th century, humanity was not exempt from falling back on the foibles of paranoia, suspicion, and fear when the going suddenly got tough. Homefront and Paradise Lost are prime examples of that message — not the destruction of 'Gene's vision,' but the vigilance needed to see it through.

Both episodes are a permanent reminder that, in times of crisis and doubt, we must not sacrifice our personal liberties to the excesses of state security and surveillance. It is all too easy to fall into the trap laid out for us — to start seeing the enemy everywhere, even in those nearest and dearest. The Founders didn't need to invade Earth, they just needed to make it look like they had. Thankfully, the likes of Joseph Sisko knew how to be stubborn when stubborn was exactly what was needed.

T'Pol, Garashir, CURZON Dax, Harry Kim, or rather, Harrys Kim, all under the command of William Boimler on a Defiant-class ship. What more could you ask for? Oh, yeah! Only Lily flippin' Sloane!

The first half of the series finale of Star Trek: Lower Decks (yes, we are counting it) was more than mere cameos and guest stars for the sake of it. Fissure Quest was a bona fide brilliant story — traversing the multiverse in search of the bad guys who turned out to be the good guys who hadn't quite thought things through. Its cliffhanger was as hilarious as we'd come to expect, and more than a touch climactic — "Holy f**k! We're all gonna die!"

As follow-up, and conclusion to five seasons, The New Next Generation was extremely satisfying. The gate at Starbase 80, or Starbase 80 at the gate, was, in itself, the possible set-up for what could be an intriguing spin-off series across the multiverse. We're still hoping for more from Lower Decks in some form, now with a new captain, and two provisional first officers.

Star Trek's very first two-parter could have just been Star Trek's very first clip show — of a pilot nobody had seen at the time. Instead, its framing device was largely clever enough to be captivating from the get-go, even if you have seen The Cage in the interim.

As The Menagerie, Part I begins, the Enterprise has been called to Starbase 11, only to find that the messenger could never have sent the message. The teaser ends with a shock revelation. Spock is about to commit treason and mutiny, and it all has something to do with his former captain, Christopher Pike.

Spock's plan is partly interrupted by his court-martial, or so it would seem. The Menagerie's solution to its fourth wall break is that it was all a Talosian transmission. "Lock him up" (and the death penalty) was then Star Trek's original cliffhanger — "To Be Concluded Next Week". Fortunately, the court-martial itself was all an illusion too, affording Captain Pike the same measure of salvation.

Star Trek likes its Latin titles, in this case far more effective, far more comprehensible in translation — from Ovid's Metamorphoses, "tempus edax rerum," or "time, devourer of all things".

The Star Trek: Prodigy second season two-parter, The Devourer of All Things, reversed the notion, introducing us to a new species that feasted on time itself. The Loom, a terrifyingly tentacled trans-dimensional foe, fed on their victims until they were erased from it. We 'big kids' were scared in equal measure.

The Devourer of All Things, Part I also marked the triumphant, greater than a cameo, return of a former acting-ensign-ensign-cadet-dress-uniform-at-a-wedding. "I'm Wesley Crusher, and I've been waiting for you." We'd been waiting for you too, Mr Crusher, though hardly expecting you. This had been kept more of a secret than the Omega molecule!

"You blew up your own shop, Garak!" Well, of course he did! The truth is usually just an excuse for a lack of explosives. Improbable Cause and The Die Is Cast gave us a few more answers to the mystery that was Garak. The rest was the same lie twice, and a horrendous time for Odo.

Factually, this was the first two-parter in Star Trek to have two separate names, although The Homecoming and The Circle both ended on 'To Be Continued,' and concluded in The Siege. Also a matter of record, Improbable Cause and The Die Is Cast began life as a standalone episode that eventually evolved to become two.

That late-stage decision meant that both episodes were shot out of sequence — Through the Looking Glass was filmed before The Die Is Cast. An isolinear rod a day won't keep the Obsidian Order away!

'Equinox' or 'equal night' is more than just the name of the Nova-class, lending itself to the title of the two-parter. As Starfleet officers, and as Starfleet officers in similarly stranded situations, the abhorrent actions of Rudy Ransom and crew cast a long shadow over Voyager, too. There also, but for the grace of a bigger ship, go we.

As a set of episodes, Equinox and Equinox, Part II benefit from an absorbing, well-executed premise, backed by Jay Chattaway's heart-pounding score, and accompanied by an acting masterclass on the part of Kate Mulgrew and John Savage.

Janeway's 'dressing-down' of Ransom, and his subsequent attempt at a defence, was nothing short of exquisite to watch. And, whatever you thought of her methods, Janeway's determination to pursue the Equinox crew for their crimes was played to pitch perfection.

Sela steps out of the shadows. Data sticks it to Lieutenant Commander Hobson on the Sutherland. Enough said! Next entry. Naturally, there's more to Redemption and Redemption II than that — a Klingon civil war, funnelled and funded by the Romulans, and one half-Romulan in particular.

Klingon in-fighting (whatever next!) is not to everyone's taste. But even those with a blood pie optional palate must recognise that Redemption and Redemption II are objectively excellent. As well as letting us see parallel Natasha Yar's daughter, Redemption also introduced us to the famously boob-windowed Duras sisters. They were good fun, too, until they forgot to replace their plasma coils!

The length of Scorpion's cold open is inversely proportional to the punch it packs. In only a few seconds, several Borg cubes go from standard self-assurance to blown to smithereens. Who could be more powerful than the galaxy's most devastating assimilators? Four numbers, that's who. You know the ones, and the 8472s!

Of course, beyond interdimensional warfare with Voyager in the middle up the Northwest Passage, the Scorpion two-parter also gave us one of Star Trek's most beloved, most enduring characters — Seven of Nine, now Captain of the Enterprise-G. For that reason alone, Scorpion deserves its high place on this list. Captain Janeway's "appeal to the Devil" might not have been popular, but it paid off!

As detailed in The Star Trek: The Next Generation Companion, Unification I & II began life as an idea from then Paramount president Frank Mancuso. As well as including references to the future in Star Trek VI: The Undiscovered Country, Mancuso wanted to find a way to bring Spock into The Next Generation for Star Trek's 25th anniversary. Rick Berman met with Leonard Nimoy to discuss the story.

The result was iconic, so much so that two- is now technically a three-parter, thanks to Star Trek: Discovery's third season, the titular dream having been achieved on the re-named Ni'Var. Then, if not the fourth part, the finest of addenda, OTOY and the Roddenberry Archive's 765874 — Unification most recently reunited Spock with his former captain and friend at the very end.

There is only one negative for Year of Hell, perhaps two, depending on your opinion of temporal do-overs. The two-parter had partly been 'spoiled' in advance in Before and After, that 'spoiler' then conveniently forgotten about post-Kes. Otherwise, it is as calculably perfect as anything calculable can be.

"It's strange, thinking there's a piece of your life you don't know anything about," Captain Janeway would say much later to Chakotay in Shattered. That strange irony exists with the viewer. We have access to information, to events, that the characters do not. The beauty of Year of Hell and Year of Hell, Part II is the high-stakes testing ground without the repercussions. "Time's up," time begins again. We still know exactly how hard Janeway and crew fought for that fresh start.

The sound of screens clicking off is as loud as the voice of the Borg Collective itself. The Best of Both Worlds isn't number one?! No, but hold your fire! For as good as it is, after 35 years we feel it's time to let another take the top spot. Besides, as someone else who went to space once said, "Second comes right after first".

The Best of Both Worlds was only the second two-parter in all of Star Trek (Encounter At Farpoint was a feature-length). It changed the game, upped the ante, and firmly solidified Star Trek: The Next Generation's place as worthy successor after an already much stronger season three. It will forever be one of the finest pieces of television ever made.

Now, wait a summer to see if they killed Captain Picard or not!

Last Flight of the Protostar, Parts I & II were always number one on this list. With the recent news that seasons one and two of Star Trek: Prodigy will soon be leaving Netflix, their place could not be more timely. Simply put, this two-parter is sublime.

Visually stunning, highly innovative, heartwarming and heartbreaking, Last Flight of the Protostar is masterful at every move. Chakotay, the Captain who has lost his crew, gets his chance to shine, stranded on Ysida for ten years. Launching a starship out onto an ocean of vapour was then one of the boldest, most beautiful, things to be put to Star Trek.

Whatever the future holds for Prodigy, it has already left an indelible mark on the franchise. It has reminded us that 'grown up' is not necessarily synonymous with 'growth,' that being an adult doesn't mean you have to pretend you're no longer a child. Anyone who tells you they've got their ship together is either lying or a Loom. All any of us can truly do is set sail, and then, hope to fly!