10 Best Star Trek The Original Series Episodes

4. The Doomsday Machine

As far as TV openings go, The Doomsday Machine's has to be one of the most ominous out there.

Investigating what appears to be a distress signal from the Enterprise's sister ship, the U.S.S. Constellation, Kirk orders his ship to warp to their last known coordinates and discovers the ship floating in space, heavily damaged, and with no means of communication.

Following a quick investigation, it turns out that the Constellation had been tracking what can only be described as the forebear to the Death Star. It's been destroying planets left, right, and centre, and the Enterprise - though an equipped vessel - is clearly outgunned. What follows makes for one of the most dramatic, intuitive and tense Trek episodes of all time, as we see the Enterprise engage in a literal David v Goliath encounter with a ship that's ended more lives than a newly de-cloaked Bird of Prey.

This is where Star Trek's bridge dynamic works best, with all the Enterprise crew rallying together to solve a problem on their own bridge in the arrival of Commodore Matt Decker, an unstable maverick determined to bring the Doomsday Machine down even if it comes at the cost of Kirk's allies.

It's just fantastic, and typifies the strengths of the show's characters as much as it does the genius of Roddenberry's concept itself.