From time travel to Tribbles: Here are the best Star Trek episodes from every series

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Over its five decades, no science-fiction property has had more of an effect on the genre than Star Trek. Five television series, an animated cartoon, and a dozen movies have captivated Trekkies for generations. While the show has occasionally produced some kitschy dialogue and plot lines that are cringe-worthy, there are many episodes that withstand the test of time as some of the greatest sci-fi adventures ever put on a screen.

In preparation for the forthcoming new series from CBS, Star Trek: Discovery, we glossed hundreds of episodes from each live-action series and picked some of our favorites for you to enjoy, whether you’re new to the franchise or a life-long fan. We’re sure this will cause a lot of discussion, but if you really want to go where no sci-fi adventure has gone before, here are the 20 episodes you’ll want on your watch list.

Star Trek: The Original Series

Set in the 23rd century, Star Trek: TOS follows the five-year mission of the USS Enterprise, with Captain James T. Kirk (William Shatner), first officer and half-Vulcan Spock, the ever cantankerous ship’s Doctor Leonard McCoy (DeForest Kelly), Uhuru (Nichelle Nichols), Sulu (George Takei), and the rest of the gang, alongside a host of alien species.

The winner

Season 1, episode 28: The City on the Edge of Forever

The final episode of the original series’ first season gets our nod for its solid storyline. Some of the episodes of TOS seemed to suffer from gimmicky — if not corny — plots, but Roddenberry and his team thread the needle well in this one. In fact, it was good enough to receive the 1968 Hugo (the Emmys of sci-fi) for Best Dramatic Presentation.

In this episode, Kirk and Spock must travel back in time to go after McCoy, who, in a fit of delusion following an accidental overdose of Cordrazine, transports down to the nearest planet. This planet is home to a time portal, and McCoy enters the portal. The incident alters the time line, causing the Enterprise and the entire Federation to disappear. Kirk and Spock bargain with the “Guardian of Forever” to enter the portal, which takes them back to 1930s New York City. What unfolds is a story about timelines that might have been, a device later used by J.J. Abrams in the series’ cinematic reboot.

Honorable mentions

Season 2, episode 4: Mirror, Mirror

Another alternate timeline story, this one again traps our heroes in an alternate reality. An ion storm sends Kirk, chief engineer Montgomery “Scotty” Scott, McCoy and communications officer Uhura to a parallel universe where the Terran Empire replaces the Federation. The alternate reality replaces the Enterprise’s mission of peace and exploration to one of conquest, and ascending in rank means killing your commanding officer.

Season 1, episode 22: Space Seed

No list of the best TOS episodes would be complete without the greatest Trek villain of them all, Khan Noonien Singh. The Enterprise stumbles upon Khan’s ship, the SS Botany Bay, and renders assistance. Little do they know, however, that Khan is the leader of a group of superhumans left over from the Eugenics Wars — a fight over genetic engineering. Before long, Kirk is fighting for his ship and possibly the future of the Federation against a man who is much stronger, smarter, and cunning than he. Khaaaaaaan!

Season 2, episode 15: The Trouble With Tribbles

This episode does have the kind of gimmicky and corny plot we bemoaned earlier. However, The Trouble with Tribbles is one of those episodes that just makes you smile, if only for the reactions of the crew to the seemingly unlimited reproductive capabilities of these furry (and cute) little creatures.

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