The Alternative Factor ( episode ) Investigating the cause of a massive , galaxy - wide disruption in space , the " Enterprise " finds a mad scientist who claims he is being pursued by a hideous being . Summary . Teaser . In standard orbit around an iron - silica - type uncharted planet , the prepares to complete its survey , when the starship is violently rocked twice and everything within sensor range suddenly " blinks " , almost as if the universe is on the verge of ceasing to exist . And , in the wake of this , a man appears on the surface of the planet , where moments earlier there was no life . Act One . Beam ing down , Captain Kirk , Spock , and the landing party encounter a man . " " You came ! Thank the heaven s , it ' s not too late ! " " , he exclaims . Dirty and disheveled , he falls from a rock . The landing party returns to the " Enterprise " with him , where Kirk learns more news – the strange phenomenon drained the dilithium crystals almost completely . Still worse , Starfleet Command issues a Code Factor 1 message – invasion status . The effect experienced by the " Enterprise " was also experienced everywhere in the galaxy , and far beyond . Starfleet withdraws all nearby ships – Commodore informs Kirk that the " Enterprise " is the bait . In his quarters , Kirk talks to his " guest " – a man named Lazarus , who is pursuing a " thing , " a monster who destroyed his entire civilization . He informs Kirk that he will stop at nothing to destroy it . Beaming back down to the planet , Kirk learns from Spock that there is no other creature here . Spock , accusing Lazarus of lying , states " " I fail to comprehend your indignation , sir . I have simply made the logical deduction that you are a liar . " " Kirk demands the truth – and the universe turns inside out once again . The same " winking " phenomenon occurs again . And Lazarus . . . first he has a bandaged forehead , and then he doesn ' t , and then he does again . Act Two . Meanwhile , Spock has discovered a source of radiation that is not there – a " rip " in the universe , where regular physical laws do not apply . The key to locating this source seems to be the dilithium crystals – a revelation which excites Lazarus , who demands the impossible : that Kirk give him the crystals . The captain refuses , but Lazarus overpowers Lieutenant Charlene Masters as well as an engineering officer and steals two dilithium crystals , nevertheless . Act Three . In the briefing room , Kirk confronts Lazarus , but he denies it , blaming his monster . And the evidence suggests he isn ' t the thief , for the crystals are not aboard his ship . In Sick Bay , Kirk confronts Lazarus with his lies , and learns that Lazarus distorted a fact : he is a time travel er . The dead world the " Enterprise " orbits is the distant future of his destroyed homeworld ; the place and time he has traveled to in pursuit of the monster . At Dr . McCoy ' s urging , the crew departs Sick Bay to allow Lazarus to rest and recover from his fall . Having relocated to the briefing room to consider all of the known evidence , Kirk and Spock conclude that the strange energy must come from a source outside the universe . A source in another , parallel universe . There are two copies of Lazarus , and they are periodically exchanging places through a kind of door – and if they ever exist in the same universe at the same time , everything , everywhere , will be annihilated in a cataclysmic matter / antimatter explosion . Meanwhile , the alternative Lazarus creates a diversion by starting a fire in main engineering , steals the ship ' s energy crystals , then beams down . Kirk pursues . As he attempts to enter Lazarus ' spaceship , he vanishes , hurled through the corridor into the other universe . Act Four . Once there , Kirk meets the other but sane Lazarus - B , and learns the truth . Lazarus - B ' s people discovered how to pass through the negative magnetic corridor that both connects and protects the two universes . When this happened , Lazarus - A couldn ' t bear the knowledge that he had a duplicate , and resolved to destroy his opposite . He is mad and doesn ' t care if this causes the destruction of two universes . Lazarus - B and Kirk realize he must be stopped : if Kirk can force Lazarus - A into the corridor , Lazarus - B can hold him there , and Kirk can destroy his spaceship – which will also destroy Lazarus - B ' s spaceship . Access to the corridor will be sealed forever and both universes will be safe , but the men named Lazarus will be at each others ' throats for the remainder of eternity . Kirk goes back through the corridor and fights in hand - to - hand combat forcibly throwing Lazarus - A into the " dimensional door . " Kirk heads back to the " Enterprise " , ordering the Lieutenant Leslie to bring the ship ' s phasers to target the inter - dimensional ship . The two Lazaruses meet once more and fight as phaser beams vaporize the ship , sealing the two for all of eternity , caught together , between universes . Kirk ruminates on the fact that the two Lazarus are going to be at each other ' s throats for all time and wonders how it would be . Spock reminds Kirk that the universe is now safe . " " For you and me . But , what of Lazarus ? What of Lazarus ? " " Memorable quotes . " " I want facts , not poetry . " " " " He ' s death ! Anti - life ! He lives to destroy ! " " " " I told you , it was the thing ! All white , black and empty . A terrible emptiness . " " " " Let ' s get back to the ship . " " " " He ' ll kill us all if we don ' t kill him first ! Kill ! Kill ! Kill ! ! Kill ! ! Kill ! ! ! " " " " Are you deaf as well as blind ? ! " " " " I fail to comprehend your indignation , sir . I ' ve simply made the logical deduction that you are a liar . " " " " Sometimes pain can drive a man harder than pleasure . " " " " Jim , madness has no purpose or reason . But it may have a goal . " " " " If they meet . " " " " Annihilation , Jim . Total , complete , absolute annihilation . " " " " So you ' re the terrible thing ? The murdering monster ? The creature ? " " " " Yes , captain . Or he is . It depends on your point of view , doesn ' t it ? " " " " You ' ll be trapped inside that corridor with him forever . At each other ' s throats throughout time . " " " " Is it such a large price to pay for the safety of two universes ? " " " " Captain , the universe is safe . " " " " For you and me . But what of Lazarus ? What of Lazarus ? " " Background information . Remastered information . " The Alternative Factor " was the forty - ninth episode of the remastered version of " The Original Series " to air . It premiered in syndication on the weekend of and aside from the standard CGI replacement footage of the " Enterprise " and the planet - of - the - week , this episode also featured several new , modest effects shots of the alternative warp effect , as well as phaser and transporter effects . Links and references . References . abrasion ; alternative warp ; antimatter ; bandage ; battle stations ; blindness ; " Bones " ; bruise ; bull ; cartographic section ; Code Factor 1 ; coffee ; commodore ; computer bank ; ; deaf ; devil ; dilithium ; dizziness ; dinosaur ; Earth ; energizer / energizing circuit s ; energy ; experimentation chamber ; explosive s ; Fahrenheit ; footprint ; forehead ; general alert ; gravimetric field ; heaven ; Hell ; Human ; hydrogen ; iron ; Lazarus ' planet ; Lazarus ' spaceship ; life survey ; logic ; magnetic communication satellite ; magnetic effect ; magnetic field ; matter ; medic ; Milky Way Galaxy ; muscleman ; negative magnetic corridor ; ounce ; oxygen ; parallel universe ; paranoia ; parsec ; phaser bank ; photographic section ; physician ; poetry ; powder keg ; priority one ; prison ; pulsation phenomenon ; quadrant ; radiation ; recuperative powers ; red 2 message ; rip in the universe ; safety valve ; silica ; spaceship ; Starbase 200 ; Starfleet Command ; time chamber ; time ship ; time traveler ; water ; zero gravity Uneferenced material . biological lab ; ; rose