Tomorrow is Yesterday ( episode ) The " Enterprise " is hurled back in time to the year 1969 , where the US Air Force sights it as a UFO . The crew must find a way to erase evidence of their visit before trying to get back to their future home . Summary . Teaser . At an Air Force base in 1969 , an airman by the name of detects something on his RADAR . At first , his commanding officer believes it to be an enemy aircraft . The signal is over Offutt AFB near Omaha , Nebraska , but the strange part is that it just appeared . It is as if it simply dropped out of the sky . Interested by the strange appearance of this aircraft , Webb ' s commanding officer orders someone to go up there and take a look . He believes they may have a real UFO on their hands . Outside , a military F - 104 fighter is launched . In the sky , the starship is gliding through the clouds . Act One . Except for secondary systems , everything is operational and they are heading on impulse power . Chief Engineer Montgomery Scott brings on auxiliary power from engineering , and Captain James T . Kirk asks to report damage and casualties to First Officer Spock . Kirk asks Uhura to contact Starfleet Control , to advise them of the black star ' s close proximity to Starbase 9 . Casualty reports show nothing more than minor injuries . Scott reports that warp engines are offline , and he is holding them at impulse in orbit over Earth . The breakaway from the star threw the ship to Earth . They are , however , in a low orbit , and Kirk orders Sulu to use impulse to rise to a higher orbit . Sulu reports that the helm is answering but is a little sluggish . Uhura reports that there is no response on any standard Starfleet channels ; however , she is getting something on another frequency . A radio broadcast states that the first manned moon shot is to take place on Wednesday . Kirk recalls that the first manned moon shot took place in the late 1960s . Spock concludes that the " Enterprise " is also in the 1960s , having been thrown backward in time by the black star ' s whiplash . Uhura reports that she is picking up ground - to - air transmissions . A military craft is approaching the " Enterprise " , fast . The craft , designated " Bluejay 4 " , is gaining on the UFO ( " Enterprise " ) . Kirk orders Sulu to gain altitude faster . " Bluejay 4 " states that the UFO is climbing , and he will go in closer . As he raises altitude , Blackjack ( the Omaha base ) states that " Bluejay 4 " should be close enough for visual contact . " Bluejay 4 " spots the " Enterprise " , which is climbing in the sky , amazed at its size . He starts to describe the UFO , and tries to determine what purpose the cylindrical projections might serve . Blackjack states that backup forces should rendezvous in about two minutes , but " Bluejay 4 " remarks that the UFO is not going to be there by then . Blackjack gives order to shoot down the UFO , or at least disable it . Spock concludes that the aircraft may be armed with nuclear warhead s , which in the " Enterprise " s severe condition , could possibly cause serious damage to the hull . Kirk orders Scott to lock on with a tractor beam , but Spock advises against it . Scott locks on , regardless , and the aircraft begins to break up . Kirk orders the pilot beamed aboard . He goes to the transporter room to meet the pilot , and welcomes him aboard . The pilot is surprised to learn that Kirk speaks English , and gives his identification as Captain John Christopher of the United States Air Force , service number 4857932 . Kirk remarks that the captain is among friends , and introduces himself . Captain Christopher asks Kirk who they are , and what happened . Kirk states that all will be revealed in good time , but Captain Christopher is understandably impatient . On the bridge , Spock reports that the aircraft has broken up . They turn off the tractor beam , and Kirk takes Christopher to the bridge . Christopher seems surprised to see a woman in the halls . Christopher admires the size and complexity of the ship , and as Kirk explains that the ship is one of twelve like it in service of the United Earth Space Probe Agency . He freely admits that he is from the future . On the bridge , Christopher ( after joking about " little green men " ) is taken aback by Spock ' s skin tone . As Kirk allows Christopher to look around the bridge , Spock expresses his concerns about their guest to Kirk privately . As Christopher looks around , Spock reports that most main systems have been restored , including the main deflector , which will prevent them from being detected again . Spock also expresses concern for Christopher ' s presence . He states that Christopher cannot return to Earth , as this could alter the course of history . Kirk states that this is an annoying conclusion , but accepts the truth . He asks Spock to get Captain Christopher some more comfortable clothes , and to bring Christopher to his ready room . In his quarters , Kirk makes a computer recording . Kirk also gets annoyed by the computer ' s frequent references to him as " dear " . Kirk asks Spock to fix the computer ' s affection . Spock explains that the computer had recently been overhauled on the female - dominated planet Cygnet XIV ( who thought the computer needed a personality ) . Christopher finds the computer system amusing , and would love to see how the dilemma works out . It is at this point , that Kirk breaks the news to Christopher that he cannot be sent back with information he now knows from the future . Christopher asks about his disappearance , but Spock says that Captain Christopher made no relevant contribution to history . Christopher says that this is an outrage , having a wife and children back on Earth , something which seems to catch Spock ' s attention . He says it is his duty to report what he has seen , but Kirk says that the risk is impossible . Kirk offers his heartfelt apology . Scott calls to tell Kirk that the engines will be operational in about four hours , but they have nowhere to go in this time . Kirk understands . Christopher finds some comfort in the fact that Kirk and his crew cannot go home themselves . Act Two . Finally getting fed up with the computer , Kirk asks it to record that it either be repaired , or scrapped , which seems to take care of the computer problem . Spock calls Kirk , stating that he has new information regarding Christopher . Kirk orders Spock to report to his quarters , and that he will call Captain Christopher . However , Christopher does not respond to Kirk ' s hails . Kirk orders a security alert , noting that Captain Christopher is not in his assigned quarters . Kirk hypothesizes that he may be trying to escape , and goes to find him . Christopher is indeed trying to escape , but runs into security officer Bobby on his way to the transporter room . He takes out the security officer , and acquires his phaser . Entering the transporter room and pointing his phaser at Kyle , Christopher tells Kyle that he wants to be transported to the surface immediately , but before he can complete his escape , Kirk comes , disarms Christopher , and knocks him out . In sickbay , Dr . McCoy reports that the injuries are superficial , and Kirk sympathizes about Christopher ' s want to escape . It is at this time that Dr . McCoy says that they too are just as stuck as Christopher . They can ' t beam down the entire crew , as it would be too great a disturbance in the timeline . Kirk however , says that " Enterprise " is not at that situation yet , but even if they do get back to their time , Christopher would be useless , archaic . McCoy says that he may be able to be retrained , but Christopher says that he cannot forget his family . He remarks that he is feeling fine , and Spock comes to sickbay . They cannot keep Christopher aboard , because his son , Colonel Shaun Geoffrey Christopher , did make an historic contribution , heading the first Earth - Saturn Mission . Christopher remarks that he has no son , to which McCoy responds , " yet " . Kirk realizes that they must find a way to return Captain Christopher , and Christopher himself muses of the fact that he someday will have a son . In orbit of Earth , Spock states that the biggest problem they must deal with is that Christopher ' s plane wreckage landed in open land ( " an open section of Southern Nebraska " ) , so search parties will know that he wasn ' t on the plane . Also , Captain Christopher informs them that his radio conversation was recorded , and that his wing cameras were recording the " Enterprise " . Kirk remarks that these UFO sightings were usually taken for explainable things , but Spock remarks that their tractor beam destroyed the plane , making them nothing else but a genuine UFO . Kirk then asks about returning them to their own time . Spock has a theory , albeit complicated , which may work . Kirk then makes a plan ; they need to destroy the hard evidence of their presence , so that if Christopher reports , there is nothing to support his claims , and he simply joins the ranks of one of thousands who has seen a UFO . Christopher then offers his help , and he sketches out a layout of the base on a PADD . At the base , Kirk and Sulu beam down , Sulu with a bag for the tapes . They are a bit disoriented at first , but soon find the correct room . They force the door open with little difficulty using their technology . Upon entry , Kirk starts to look for what they need , and soon finds the audio tapes . On the " Enterprise " in the transporter room , Dr . McCoy is getting nervous , but Spock reassures him , noting that stealth missions are much more complicated than others . McCoy starts to get annoyed , and asks Spock whether he should be working on his time warp calculations , to which he calmly responds , " " I am . " " Back at the base , Kirk and Sulu finish getting the tapes , when a Security Police staff sergeant enters . He orders them to give him the belts and the bag , with the tapes inside . On the ship , Spock now agrees with McCoy and starts to think it has been too long , so he calls the captain . The security officer opens one of the communicator s , transmitting an emergency signal . Spock orders an immediate beam - up , only to find that they beamed up the wrong man . They now have two undesired passengers aboard , and the sergeant is frozen out of both surprise and fear . Kirk calls Spock , reporting that they now clearly have another problem . Act Three . Kirk informs " Enterprise " about their " surprise package " , and asks them to keep him in the transporter room . After finishing up in the audio tape section , both Kirk and Sulu go to retrieve the video tapes of " Enterprise " . They find them in the dark room , but set off a silent alarm . They finish collecting the video , but after a small brawl with some security officers , Kirk gets caught . Sulu however , seems to have disappeared . He managed to beam up , with the tapes , and Kirk calmly explains to the curious guard that it was only he who was prowling about . On the " Enterprise " , Scott reports that warp engines are ready for re - firing . Spock orders them to be , so that they can have full power . Down on the surface , Kirk is being interrogated by the guards who caught him . Kirk jokingly references that he got in to the base by popping in out of thin air . Lieutenant Colonel Fellini picks up Kirk ' s phaser , mistaking it for a radio transmitter . Then he wonders about Kirk ' s uniform and he starts to list Kirk ' s offenses , threatening to lock him up for 200 years . Kirk ruefully comments that that ought to be just about right ( to return him to his own era ) . Back in orbit , Spock and Christopher hypothesize in the " Enterprise " s briefing room as to the captain ' s most probable situation , as they are planning a rescue operation . However , Christopher insists on coming down with them , to which Spock reluctantly agrees . He issues phasers only to himself and Sulu , set on maximum stun . They beam down , as the security policeman who beamed up earlier is amazed . Kyle offers the guard some chicken soup from a food synthesizer to satisfy his hunger , which only amazes him more . On the surface , Spock takes out the two guards holding Kirk , and frees him . However , while Kirk and Sulu talk , Christopher gets one of the security guard ' s guns . He holds it to Kirk , refusing to be beamed back up . Act Four . Kirk tries to talk Christopher out of it , but he doesn ' t listen . He asks Spock to come out of Colonel Fellini ' s office , but as he moves towards Kirk , Spock comes up from behind , and administers a nerve pinch . He had suspected Christopher ' s actions , and had beamed into location for incapacitating Christopher . Sulu then beams up all four officers . 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 . Scott now brings up one problem . The " Enterprise " may not have enough braking control to stop in their own time . They may overshoot their century , or be torn apart . In other words , it won ' t be an easy ride . Everyone assumes stations , as the " Enterprise " prepares for the time - warp . They leave Earth , and head towards the sun at warp factor 3 . Christopher , at this point , tells Kirk how he always wanted to make it into space , and Kirk tells him that he made it farther than anyone in his century . As " Enterprise " heads towards the sun , their warp factor increases , and the chronometers have started to move backwards . Christopher goes to put on his flight gear , and reports to the transporter room . As they approach the breakaway point , Sulu engages engines , and the ship is severely thrown . All power is just barely enough , but they do break free of the pull . As they head away from the sun , they gain speed , and the chronometers begin to move forward . Christopher prepares to beam back to Earth , and thanks Kirk for the look ahead . As they approach Earth , they energize , beaming Christopher back into the plane cockpit . However , there is no longer any " Enterprise " in the sky . Christopher reports to Black Jack , marking down " Enterprise " as another UFO . They then beam down the guard , but he too finds no unusual activity at the base . As they approach their century , they have to begin braking , despite some risks . Kirk , being annoyed by Spock ' s countdown , asks him to just never mind . They begin braking , but the ship is thrown violently . Scott reports from engineering that the engines are buckling , but they manage to make a safe and complete stop . They hear the friendly voice of Starfleet control , and Kirk reports that the " Enterprise " is home . Memorable quotes . " " I never have believed in little green men . " " " " Neither have I . " " " " Don ' t touch anything , but I think you ' ll find it interesting . " " " " Interesting is a word and a half for it , captain . " " " " Maybe I can ' t go home , but neither can you . You ' re as much a prisoner in time as I am . " " " " Now you ' re sounding like Spock . " " " " If you ' re going to get nasty , I ' m going to leave . " " " " I made an error in my computations . " " " " Oh ? This could be an historic occasion . " " " " Wait a minute . I don ' t have a son . " " " " You mean yet . " " " " It is a fact , Doctor , that prowling by stealth is more time - consuming than a direct approach . " " " " How did you get in ? " " " " I popped in out of thin air . " " " " What is that ? Is that a uniform of some kind ? " " " " This little thing ? Just something I slipped on . " " " " I am going to lock you up for two hundred YEARS ! " " " " That ought to be just about right . " " " " Blast your theories and observations , Mr . Spock ! What about Jim ? He ' s down there alone , probably under arrest ! He doesn ' t have a communicator and we can ' t locate him or beam him back aboard without one ! " " " " I am aware of that , doctor . " " " " Anyway we do it , it ' s a mighty rough ride . " " Background information . Apocrypha . The second issue of John Byrne ' s " " series , " Yesterday , Today and Tomorrow " , tells the story of Gary Seven ' s role in the events of this episode . Remastered information . The remastered version of " Tomorrow is Yesterday " aired in many North American markets during the weekend of . The episode was heavy in new effects , with revamped CG shots of Earth from orbit – based on NASA space shuttle photographs – as well as new CGI shots of Captain Christopher ' s jet fighter , the " Enterprise " falling into Earth ' s atmosphere and an all - new sequence depicting the slingshot around the sun . Links and references . References . 1954 ; 1968 ; 1969 ; 2217 ; . 38 police special ; 498th Air Base ; ADC Control ; Air Defense Command ; Alpha Centauri ; Apollo 11 ; astronaut ; B - 52 Stratofortress ; black hole ; blackjack ; blip ; " Bluejay 4 " ; Cape Kennedy ; chicken soup ; ; cloud cover ; Cygnet XIV ; drawing ; Earth ; Earth - Saturn probe ; F - 104 Starfighter ; flight suit ; horse ; industry ; logic ; Luna ; ; ; mirage ; NASA ; Nebraska ; nuclear warhead ; Omaha ; Pluto ; quartermaster ; RADAR ; rubber band ; Saturn ; slingshot effect ; Sol ; Starbase 9 ; Starfleet Control ; staff sergeant ; Statistical Services Division ; Strategic Air Command ; stock ; sun dog ; time zone ; tractor beam ; truck ; United Earth Space Probe Agency ; UFO ; USAF ; US Navy ; Vulcan neck pinch ; weather balloon