Star Trek: The Original Series — The Complete Guide to Every Episode, Character, and Movie

Three seasons, 79 episodes, six feature films, and a cancellation that fans refused to accept. Here's the full picture of the show that started it all.

In February 1968, NBC's mail room logged roughly 115,000 letters in a matter of weeks — nearly all of them saying the same thing: don't cancel Star Trek. The network caved, gave the show a third season, and then buried it in the Friday night "death slot" anyway. Star Trek still ended after 79 episodes. It just never actually went away. Six decades, thirteen feature films, and nine spin-off series later, the show that NBC nearly killed twice is the reason the word "franchise" means what it means in Hollywood today.

Series Overview

Gene Roddenberry originally pitched Star Trek to network executives as "Wagon Train to the stars" — a Western dressed up in a Starfleet uniform, built around a five-year mission of exploration. NBC bought the concept but rejected Roddenberry's first pilot, "The Cage," as "too cerebral," a note that still sounds strange next to a show remembered for morality plays about war, prejudice, and first contact. A second pilot, "Where No Man Has Gone Before," won the network over, and Star Trek premiered on September 8, 1966, with "The Man Trap."

The show ran three seasons — 29 episodes, then 26, then 24 — for 79 total, plus the unaired original pilot. Ratings were never strong enough to satisfy NBC, and a mid-run budget cut visibly thinned out Season 3's production values. But the show built something ratings couldn't measure: a fanbase organized enough to save it from cancellation once, and loyal enough to keep it alive in syndication for decades after the cancellation finally stuck.

The Bridge Crew: Main Characters

Every Star Trek that came after this one borrowed its command structure from three people: a captain who leads with instinct, a science officer who leads with logic, and a doctor who refuses to let either of them forget they're human.

Captain James T. Kirk

William Shatner's Kirk commands the Enterprise with a mix of gut instinct and improvisation that became the character's defining trait — he's the captain who talks a hostile computer into shutting itself down as often as he out-maneuvers it. Kirk's willingness to break protocol when the moment demands it runs through nearly every major episode, from "The Corbomite Maneuver" to "The City on the Edge of Forever."

Mr. Spock

Leonard Nimoy's Spock, half-Vulcan and half-human, became the show's breakout character almost by accident — Roddenberry originally planned him as a minor supporting role. Spock's ongoing tension between Vulcan logic and suppressed human emotion gives the show its most consistent through-line, playing out across episodes like "Amok Time" and "Journey to Babel," which introduces his parents, Sarek and Amanda.

Dr. Leonard "Bones" McCoy

DeForest Kelley's McCoy serves as the show's moral conscience and the third point of its central triangle, forever arguing with Spock's logic from a place of blunt, often cranky humanism. The Kirk-Spock-McCoy dynamic — one part instinct, one part logic, one part heart — is the format nearly every subsequent Star Trek series would try to replicate.

"I'm a doctor, not a [insert profession here]" became McCoy's catchphrase precisely because the writers kept finding new ways to put him somewhere he didn't belong.

Rounding out the bridge crew: Montgomery "Scotty" Scott (James Doohan), the chief engineer whose relationship with the ship's limitations became a running joke; Nyota Uhura (Nichelle Nichols), the communications officer whose casting was itself a landmark for network television; Hikaru Sulu (George Takei), the helmsman; Pavel Chekov (Walter Koenig), the young Russian navigator added in Season 2; and Christine Chapel (Majel Barrett), the head nurse who first appeared as "Number One" in the original pilot before Roddenberry reworked the role.

Three Seasons, 79 Missions

Star Trek's episode order tells its own story about a show finding its identity, then losing its budget.

Season One (1966–67): 29 Episodes

The first season is where the show figures out what it is, and it does so at a remarkably high hit rate for a freshman year. "Balance of Terror" introduces the Romulans and doubles as a submarine-warfare thriller disguised as science fiction. "Space Seed" introduces Khan Noonien Singh, a one-episode guest villain who would eventually anchor the franchise's most acclaimed film. "Errand of Mercy" brings in the Klingons. And "The City on the Edge of Forever," written by Harlan Ellison, won the show its only competitive Hugo Award and is still regularly cited as the series' finest hour.

Season Two (1967–68): 26 Episodes

Season 2 opens with "Amok Time," which introduces Chekov and gives audiences their first look at Vulcan, and never really lets up. "Mirror, Mirror" invents the evil-universe-doppelganger concept the franchise would return to for decades. "The Trouble with Tribbles" is the show's most beloved comedy episode. "Journey to Babel" deepens Spock's backstory. It's the season most fans point to as the show's creative peak — right before NBC nearly canceled it.

Season Three (1968–69): 24 Episodes

The post-cancellation-scare season is uneven by most accounts, hampered by a slashed budget and a rotating slate of writers, but it isn't without highlights. "The Tholian Web" traps Kirk between dimensions in one of the show's tensest episodes. "All Our Yesterdays" sends the crew through time with real emotional stakes. And "Turnabout Intruder," the series finale, aired on June 3, 1969 — closing out the original run before Star Trek returned in animated form four years later.

Six Films, One Crew: The Movies

The cancelled show didn't stay cancelled. A decade after "Turnabout Intruder," the entire original cast returned for the first of six feature films, and the crew who'd been fired from network television spent the next twelve years anchoring one of the biggest franchises in movie history.

Star Trek: The Motion Picture (1979), directed by Robert Wise, reunited the cast in a slow, effects-heavy story that leaned hard into the "2001" era of science-fiction filmmaking. It made money but split critics and fans alike. Star Trek II: The Wrath of Khan (1982) fixed nearly everything the first film got wrong, bringing back Ricardo Montalban's Khan from "Space Seed" for a leaner, more personal story that's still widely considered the franchise's best film. Star Trek III: The Search for Spock (1984), directed by Leonard Nimoy himself, dealt directly with the consequences of Spock's death at the end of II.

Star Trek IV: The Voyage Home (1986), also directed by Nimoy, sent the crew back to 1980s San Francisco in the franchise's most purely fun installment, and became its biggest box-office hit to that point. Star Trek V: The Final Frontier (1989), directed by William Shatner, is generally regarded as the low point of the run. Star Trek VI: The Undiscovered Country (1991) closed out the original cast's era with a Klingon-peace storyline that doubled as a fitting send-off for the ensemble that had carried the franchise since 1966.

Legacy: Why It Still Matters

A show NBC tried to cancel twice now sits at the root of nine additional television series and thirteen feature films. Uhura's presence on the bridge is still cited as a landmark moment for Black actors on American television. The Kirk-Spock-McCoy triangle became the load-bearing structure every subsequent Trek captain's table would echo in some form. And "The City on the Edge of Forever" remains the only episode of 1960s network television to win a Hugo Award for Best Dramatic Presentation — a piece of trivia that says more about the show's ambitions than any ratings chart from 1967 ever could.

Where to Watch

All 79 episodes and the six original-cast films are streaming on Paramount+, with the remastered versions of the TV episodes also available for purchase on most major digital platforms.