Let That Be Your Last Battlefield ( episode ) The crew of the " Enterprise " find themselves caught in the middle of an intractable conflict with a bizarre fugitive alien and his equally belligerent pursuer . Summary . Teaser . On an urgent decontamination mission to the planet Ariannus , the encounters a Federation shuttlecraft reported as stolen from Starbase 4 . The vessel ' s life support systems are failing and the pilot may be suffocating in the lack of atmosphere . Captain Kirk orders the shuttlecraft to be brought aboard . When the pilot emerges and subsequently collapses in front of Kirk and Spock , he displays a unique appearance : black on the left side of his face and white on the other . Act One . Brought to sickbay , Kirk , Spock and McCoy surmise the alien ' s skin coloration to be a mutation of some kind . The pilot is revived by Dr . McCoy and identifies himself as Lokai from the planet Cheron . Although grateful for the " Enterprise " s rescue , he is combative when Kirk questions him about the theft of the shuttlecraft . Kirk plans to return him to Starbase 4 to face serious theft charges once the important Arrianus mission is completed . En route however , Chekov reports that sensor s have detected a highly sophisticated ( and invisible ) vessel on an apparent collision course with the " Enterprise " . At the last moment before impact , the ship appears to disintegrate , but deposits its pilot on the bridge – similar in appearance to Lokai , but with his black and white skin colors reversed . " " Explain , Spock , " " Kirk asks . " " One of a kind ? " " Act Two . The alien identifies himself as Commissioner Bele , the " Chief Officer Of The Commission on Political Traitors , " from Cheron , and informs Kirk that he has come to apprehend Lokai . When Bele is brought to sickbay to see Lokai , the crew learns that Bele has been pursuing Lokai for a very " long " time : 50 , 000 Earth years as it turns out . Bele charges that Lokai led a revolt of people who are black on the left side against the ruling order , which is black on the right side . Lokai counters that the black / right ( white / left ) order enslaved the white / right ( black / left ) people of Cheron and continues to oppress them . Bele demands that Kirk surrender Lokai , while Lokai claims political asylum with the Federation . Kirk ends the bickering , giving Bele quarters and states his intention to fulfill his mission , then hand both of the aliens to Starbase 4 to have the matter settled . Bele is clearly not satisfied , but leaves sickbay . Kirk advises that Lokai get some rest , especially his vocal cords , as he will get a chance to practice his oratory when they arrive at Starbase 4 . Suddenly , the " Enterprise " is commandeered by an unknown source . Soon , Bele reveals on the bridge that he is controlling it , by using his mental powers to direct the ship to Cheron . Impervious to phasers , Kirk , along with Spock and Scotty , are forced to activate the three - part self - destruct sequence in order to force Bele to relinquish control of the ship . Act Three . With only six seconds left before the " Enterprise " destroys itself , Bele releases control of the starship . With force not being an option , both Bele and Lokai attempt to enlist the sympathies of the crew while en route to Ariannus , Lokai with the crew and Bele with Kirk and Spock . Kirk submits a report to Starfleet Command for a resolution . Starfleet ' s answer to Bele ' s request is received while he speaks with Kirk and Spock - - and it is to deny that request . Since Cheron has no diplomatic treaties with the Federation , Starfleet cannot extradite Lokai without due process . Uhura also adds that the decision from Starfleet notes that they are confident that Bele will be allowed to return to Cheron with Lokai after the hearing is over . Bele is pessimistic , however , believing that Lokai will again gain supporters in his cause and will escape from him again . The " Enterprise " arrives at Ariannus and begins the decontamination procedures . Once the decontamination mission to Ariannus is complete , Kirk orders to head to Starbase 4 , however , Bele sabotages the self - destruct mechanism as well as directional control , regains control of the ship , and re - forces it to head for Cheron again . Act Four . Lokai begs for the Enterprise crew to intervene , and Bele berates him , for he believes he has finally caught him . They fight , but Kirk tries to defuse the situation for fear of destroying the ship , saying the bridge will be their " last battlefield . " Bele returns control , since their fighting will destroy themselves with the ship . The crew realizes they are near Cheron , however , its sensors reveal massive destruction of all Cheron ' s major cities and huge piles of unburied corpses – the entire population of Cheron has apparently mutually annihilated itself in a civil war . Consumed with mutual insane hatred and blaming each other for the resulting holocaust , Bele and Lokai fight on the bridge , despite Kirk ' s offer for them to live with the Federation . Kirk implores them to give up their mutual hatred of one another , since that destroyed their planet and their people . Lokai derides Kirk , accusing him of being an " " idealistic dreamer , " " and flees the bridge . The pair then chase each other through the ship ' s corridor s , each eventually finding their way to the transporter room and returning to the planet ' s surface to continue their fight . . . the last two sapient life forms on a dead planet . Kirk sadly notes that , in the end , all they have left is their hatred of each other . Kirk decides to leave them there and orders that Sulu set course for Starbase 4 . Memorable quotes . " " We must therefore conclude that this alien is that often unaccountable rarity . A mutation , one of a kind . " " " " When in doubt , the book prevails , Mister Spock . " " " " I ' m grateful for your rescue . " " " " Don ' t mention it . We ' re pleased to have caught you . " " " " You monotone Humans are all alike . First you condemn and then attack ! " " " " I ' m very tired . " " " " And very evasive . Or , at least , not . . . fully responsive . " " " " Explain , Spock . One of a kind ? " " " " You can no more destroy this ship than I can change color . " " " " Begin thirty second countdown . Code zero - zero - zero - destruct - zero . " " " " Mr . Spock , is this ship headed for Ariannus ? " " " " Negative , captain . The Enterprise is now moving in a circular course . " " " " And at warp 10 we ' re going nowhere mighty fast . " " " " Disgusting is what I call them . " " " " There was persecution on Earth once . I remember reading about it in my history class . " " " " Yes , but it happened way back in the twentieth century . There ' s no such primitive thinking today . " " " " You ' re black on one side and white on the other . " " " " I am black on the right side . " " " " I fail to see the significant difference . " " " " Lokai is white on the right side . All of his people are white on the right side . " " " " Change is the essential process of all existence . " " " " I once heard that on some of your planets , people believe they are descended from apes . " " " " The actual theory is that all lifeforms evolved from the lower levels to the more advanced stages . " " " " Yes , he will delay , evade , and escape again . And in the process put thousands of innocent beings at each others throats , getting them to kill and maim , for a cause which they have no stake in . But , which he will force them to violently espouse by twisting their minds with his lies , his loathsome accusations , and his foul threats . " " " " What do you do ? Carry justice on your tongues ? You will beg for it , but you won ' t fight or die for it ! " " " " After so many years of leading the fight , you seem very much alive . " " " " I doubt that the same can be said for many of his followers . " " " " You ' re finished , Lokai ! Oh , we ' ve got your kind penned in on Cheron into little districts , and it ' s not going to change ! You ' ve combed the galaxy , and come up with nothing but monocolored trash , do - gooders , and bleeding hearts . You ' re dead ! You half - white ! " " " " You useless pieces of bland flesh ! I ' ll take you with me ! You half - black ! " " " " My people . . . all dead ? " " " " Yes , Commissioner . " All " of them . " " " " No one alive ? " " " None " at all , sir . " " " " Your planet is dead ! There ' s nobody alive on Cheron because of hate . " " " " Listen to me . You both must end up " dead " if you don ' t stop hating . " " " " You ' re an idealistic dreamer . " " " " Bele . The chase is " finished . " " " " He must " not " escape me ! " " " " Where can he go ? " " " " Shall I alert security , sir ? " " " " No , lieutenant . Where can they run ? " " " " It doesn ' t make any sense . " " " " To expect sense from two mentalities of such extreme viewpoints , is not logical . " " " " But their planet ' s dead . Does it matter now which one of them was right ? " " " " Not to Lokai and Bele . All that matters to them is their hate . " " " " Do you suppose that ' s all they ever had , sir ? " " " " No . . . but that ' s all they have left . " " Links and references . References . 20th century ; Ariannus ; Ariannus Ministry of Health ; ape ; bacteria ; blood ; " Bones " ; Cheron ; Cheron native ; Cheron scout vessel ; Chief Officer ; Civil Rights Movement ; Class F shuttlecraft ; Coalsack ; command frequency two ; Commission on Political Traitors ; commissioner ; " Da Vinci " ; death warrant ; destruct sequence ; directional control ; disciple ; district ; due process ; Earth ; evasive action ; evolution ; extinction ; extradition ; genocide ; hangar deck ; history ; hull breach ; intergalactic treaty ; lava ; logic ; master computer ; master race ; memory bank ; Mendel , Gregor Johann ; Milky Way Galaxy ; nucleotide ; oxygen ; political asylum ; racism ; recreation room ; recuperative power s ; red alert ; Romulan s ; sabotage ; sapient lifeform ; scope ; sentience ; shields ; skin ; slavery ; spray tank ; spouse ; Starbase 4 ; Starfleet Command ; stealth ; suffocation ; theft ; toast ; tractor beam ; United Federation of Planets ; United Fleet of Planets ; utopia ; vocal cords ; volcano ; Vulcan ( planet ) ; Vulcan s