Star Trek: 5 Great Storylines The Show Left Hanging

Over the course of more than seven hundred television episodes and twelve movies -- made over the course of half a century (and counting) -- the Star Trek franchise has covered a lot of narrative ground. We've watched as our favorite characters have grown over the course of years, even decades. We've witnessed the founding and collapse of galactic empires. And we've seen ideas that began as throw-away lines in one episode become part of a rich and complex backstory in later installments. However, a franchise doesn't endure for fifty years without having to abandon a few great storylines along the way. In the following list, we'll look at five storylines that were unexpectedly dropped before they reached a conclusion, try and explain why they weren't continued, and point out how the different ways they found resolution in a variety of (non-canon) Star Trek novels, comics, and videogames.

5. Lieutenant Thomas Riker

Introduced: "Second Chances" (TNG, Season Six)Last Seen: "Defiant" (DS9, Season Three) Lieutenant Thomas Riker was introduced on the sixth season of Star Trek: The Next Generation, a duplicate of the show's own Commander William T. Riker accidentally created by a transporter accident. After some soul-searching, he decided to stick with a career in Starfleet, and bid farewell to the crew of the Enterprise-D to assume his posting. Two years later, Tom showed up in "Defiant," an episode of Star Trek: Deep Space Nine. At first, he poses as William T. Riker from the Enterprise, but he only maintains the ruse long enough to gain Major Kira's confidence and hijack the Defiant for a mission of destruction in Cardassian space. It turns out that Tom has spent the past two years developing sympathies for the Maquis, an anti-Cardassian rebel group that broke away from the Federation the previous year. Tom is a brilliant tactician, and he uses the Defiant to destroy several targets in Cardassian space as a diversion from his main objective -- a fleet of Cardassian warships being secretly constructed in the Orias System. Tom believes the fleet is being prepared to launch an offensive to wipe out the Maquis once and for all. However, it turns out that his intelligence is out of date -- the Cardassian fleet isn't under construction, it's already built. Unable to advance or retreat, Tom brokers a deal -- he'll agree to stand trial on Cardassia if his Maquis accomplices are remanded to Federation custody. Just before Riker beams away, he kisses Kira, and she tells him, "I give you my word. We'll get you out of there, Tom. I promise you that." However, that's the last time Tom Riker is seen (or mentioned) on screen. It's unclear why the writers never found a place to revisit the story of Tom Riker. In an interview not long after the episode, executive producer Ira Steven Behr said, "We'll probably see a return of Tom Riker episode. What's nice is he's not really a part of Next Generation, so he's ours, and we can do what we want with him and not worry about what the movies will do with Will Riker." Actor Jonathan Frakes also expressed an interest in returning to the role, but another episode never materialized. By the fourth season, Tom Riker was included in a list of topics that were deemed off limits in pitches from freelance writers, and he was never heard from again. In the novels, comics, and videogames, however, several writers have sought various ways to continue or wrap up Tom's story. In the two-part comic story, "Sole Asylum," Tom is caught up in a Cardassian plot to create an army of transporter duplicates. The plot is eventually foiled, and Tom is forced to return to the Cardassian labor camps, but not before Captain Sisko promises to return for him someday. In a later novel, "Fallen Gods," it is suggested that Tom met a tragic end while in Cardassian custody. In Star Trek: Online, however, it turns out that Tom and the other prisoners of war at his work camp chose to build a community after the end of the Dominion War, where he succumbs to a heart attack sometime later.