Recap: Star Trek S 1 E 19 Tomorrow Is Yesterday

Establishing shot: Stock Footage of an air force base. The RADAR detects a signal from just over Omaha, Nebraska. The officers discuss the unusual UFO that seems to have come from nowhere. Just when we're thinking some old war movie is being played by mistake, we hear the Theme Tune and see the Enterprise gliding through a blue sky and clouds.

According to the Captain's Log, the Enterprise encountered a black star of high gravitational attraction that forced them to use all their warp power to escape the pull, which propelled them plunging through space...and time itself! There's no signal from Starfleet and the Enterprise is being tailed by a relatively primitive craft. It is, however, armed with some nuclear warheads that could do more damage than they're able to repair in this time period, so they break out the Tractor Beam. It turns out to be more than the jet can handle, so the pilot is beamed aboard. He introduces himself as Captain John Christopher, 4857932. Kirk assures him he is not a prisoner and takes him to the bridge.

So, Kirk is trapped 200 years in the past with a "guest" who doesn't want to stay, but they can't let go. The engines are shot. They have no way of contacting Starfleet. There's massive injuries from that star that slapped his ship around like a pinball. And his computer is flirting with him! With the 99 problems Kirk has, it seems that a bitch-puter is one of them!

Tropes for this episode include:

  • Captain Obvious: Spock seems to believe that's what Bones is being when he describes the danger Kirk is in.
  • Catch-22 Dilemma: Spock does some research and learns that Christopher must be returned to his timeline in order to father Shaun Christopher, who will be on a probe mission to Saturn, or else history will be disastrously changed. But if they return him, he will be duty-bound to report everything he's learned about the future, and history will be disastrously changed.
  • Changed My Jumper: Captain Kirk beams down to a 1960s U.S. Air Force base while wearing his Star Fleet uniform.
  • Deadpan Snarker: Once more, Bones mentions that Spock admitting to being wrong is a historical moment. Kirk's snarks under interrogation are the funniest moments in the show.
  • Framing Device: The 1975 Star Fleet Technical Manual by Franz Joseph credits the events of this episode as the source of all the manual's content. Somehow, USAF computers were able to download a great deal of information from the Enterprise's library computer detailing the Federation, Starships, Starfleet, and a slew of other data. How a 20th century computer is able to hack into a 23rd century computer without anyone noticing is not addressed.
  • Fish out of Temporal Water: Christopher would be one if the Enterprise took him back to the future.
  • Get Back to the Future: While breaking away from a black hole, the Enterprise is flung back in time to the year 1969. They must find a way to reverse the effect to return to their own time.
  • He Knows Too Much: The reason given for keeping Christopher on board.
  • Little Green Men: Christopher states he has never believed in "Little Green Men". "Neither have I." says Spock. When being questioned, Kirk claims to be a little green man from Alpha Centauri.
  • Mistaken for Aliens: Christopher thinks the crew aboard the Enterprise are aliens. Well, not all of them are.
  • Mistaken for Spies: The officers of the USAF assume Kirk must be a spy, trying to steal privileged information.
  • Mundanization: Space age jets are like balsa gliders compared to the Enterprise. Sulu and Kirk need to steal a pre-digital era film reel to protect the time line. Kirk marvels at the sight of an old relic known as a "cork board".
  • No Antagonist: The earthlings aren't presented as villainous, and all of their reactions to the Enterprise and its crew are perfectly understandable.
  • Now Do It Again Backwards: How the Enterprise returns to its own time.
  • Oh, Crap: Kirk gets an "Oh, crap!" look on his face when Air Force officers catch him in the act of stealing photographs. And an even bigger one as they play with his phaser.
  • Plot Hole: Selective memory erasure techniques apparently didn't exist in the 23rd century. That would have instantly solved the dilemma of returning Captain Christopher home with knowledge of the future. Spock has also shown in future episodes that he has the ability to use a mind meld to erase an unwanted memory.
  • Reckless Gun Usage: Justified; the Air Police who capture Kirk don't know one piece of his gear from another, and a hand phaser looks more like an electric shaver than any 20th-century weapon. Still, they play with it casually and toss it around. If you watch their fingers, they come within a literal hairsbreadth of shooting him or each other more than once.
  • Time Travelers Are Spies: When the Enterprise accidentally travels back in time to Earth in 1969, Captain Kirk is considered a spy when he's caught infiltrating a U.S. Air Force base. (When an interrogator threatens to lock him up for two hundred years, Kirk ruefully acknowledges, "That ought to be just about right.")
  • Timey-Wimey Ball: Here's the solution to their little problem: Mr. Spock says that the best possible course of advantage is to use a slingshot effect like the one they used to arrive in the first place. Theoretically, the whiplash from the sun's gravity would send them into another time warp. At this point, Christopher asks what they will be doing about him and the guard. Spock states that for a moment, they will go into the relative past, and transport both the captain and the guard to points before they were beamed up. The events, though still in their minds, will not have occurred, so there would be nothing for them to report. Don't think about it too much.
  • Tractor Beam: The Enterprise uses one on Christopher's plane to prevent it firing its missiles.
  • Twenty Minutes into the Future: The crew goes back in time to the late sixties—where they pick up a radio broadcast talking about a manned moon launch coming up, establishing it as being a bit later in the sixties than when the episode was made.
  • You Wouldn't Believe Me If I Told You: Kirk tells his interrogators this when they demand to know how he got in their dark room.