Arena ( episode ) Kirk battles an alien captain who destroyed a Federation outpost . Summary . Teaser . Captain Kirk and a landing party – Spock , Dr . McCoy , , Kelowitz , and – beam down to the Federation observation outpost on Cestus III at the invitation of its commander , Commodore Travers who has received quite the reputation for setting a fine table with his personal head chef . When the Away Team arrive , they discover that the invitation is a ruse and the colony has been destroyed . Act One . After the landing party takes cover and Kirk declares full alert , they discover a survivor in the ruins , Lieutenant Harold . Spock quickly locates the presence of other lifeform s nearby , but , no colony survivors . His tricorder reads them as cold - blooded creatures , but definitely not Human . O ' Herlihy scouts them out , but is immediately disintegrated by an alien weapon , as the landing party is bombarded by a massive shelling attack . At the same time , the comes under attack in orbit by an unidentified starship . With her deflector screen s up , the " Enterprise " cannot beam up the landing party . Kirk orders Lieutenant Sulu to return fire with the phaser bank s , but , it has little effect as the alien ship has screens up as well . Kirk orders the use of photon torpedo es , but , the torpedoes are ineffective , as the alien is too far away even for visual contact . The captain orders Sulu to take whatever action is necessary to protect the " Enterprise " , be it leaving orbit or engaging maximum warp . Sulu opts for the former and takes the ship away from Cestus III . Kirk makes his way to the colony ' s arsenal , avoiding large blasts from the unidentified attackers and retrieves a grenade launcher . Spock and Kelowitz rendezvous with him as the first officer reports that the enemy troops are moving towards their location . Kelowitz reports that Lang has been killed and gives Kirk his best guess as to where they have moved and Kirk launches the grenade in that direction . The tactic proves successful as the aliens begin to decamp back to their vessel , allowing Sulu to return with the " Enterprise " and retrieve the landing party and quickly set a pursuit course of the attacking ship . In sickbay , Harold tells Kirk and Spock of the attack on the colony . The aliens had knocked out their phasers with their first salvo , leaving the colony defenseless and confirms Kirk ' s earlier theory that the aliens had faked the message from the colony diverting the " Enterprise " to Cestus III in an attempt to destroy the " Enterprise " , the only protection in that part of the Federation . Such a move , a prelude to invasion , suggests the correct course : overtake and destroy the enemy , before he can return to his home base and report . The captain orders the ship to battle stations and to warp 6 to overtake the aliens . " " Red alert . I repeat , red alert . This is no drill , " " Kirk announces to the crew through the " Enterprise " s intercom . " " This is no drill . " " Act Two . The aliens , aware that the " Enterprise " is in pursuit , jumps to warp 6 as well . Kirk orders warp 7 engaged , drawing concern from Spock and chief engineer Scott that a sustained warp 7 speed would be hazardous to the " Enterprise " s warp engines . Spock argues against destroying the enemy vessel on the basis of respect for sentient life . Kirk disagrees ; his opinion is that a crime has been committed and the perpetrators must be punished . Sulu reports that the aliens have moved to warp 7 , as well . Kirk , mulling over his options , orders the ship to accelerate to warp 8 and have all weapons departments at battle ready . Closing at warp 8 , the " Enterprise " records a scanning beam from an uncharted solar system at 2466 PM . The alien is not approaching this system ; it appears that a third party is " curious " about the " Enterprise " . The alien abruptly begins to slow , going quickly to sublight speed until finally stopping dead in space . Kirk closes for the kill , but the " Enterprise " is soon slowed to sublight , as well , stopped dead like the alien with all power to the engines and weapons simply cut off . The architects of this reveal themselves : the Metron s , an advanced race who regard intrusion into their space for the purpose of conflict as entirely unacceptable . They remove Kirk from the " Enterprise " and the Gorn captain from the alien vessel and deposit both of them on a suitably - prepared world . From there , they will settle their differences , using strength and ingenuity . The winner and his ship will be free to go ; the loser and his ship will be destroyed . Act Three . The Gorn captain is reptilian , large , and very strong – but quite slow . Kirk is able to evade him initially , but knows he can ' t evade him indefinitely . He ' ll have to find a way to defeat an opponent who is far stronger and tougher . The key may lie in a comment the Metron made , that the prepared environment contains elements suitable for fabricating weapons . Attack and evasion continue for some time , with Kirk narrowly evading death at the Gorn ' s claws . Back on the " Enterprise " , the crew is unable to restore power to the engines and the weapons and remains immobilized . The Metrons reestablish communications and inform the crew that Kirk is losing the battle . In view of his impending death , they allow the crew to watch what is happening on the viewscreen . The Gorn finally communicates : it proposes that Kirk cease trying to evade him , and promises in exchange to be merciful and quick . Kirk compares this offer to the " mercy " that was shown to the Humans at Cestus III ; this enrages the Gorn , who tells Kirk his people regard Cestus III as part of their space . From the Gorn perspective , they were repelling an invading force . Watching from the bridge ( for the Metrons are now allowing this ) , McCoy posits that it is perhaps they who are in the wrong . Spock agrees it is possible . Act Four . As the conflict continues , Kirk remembers an old formula : gunpowder . Using sulfur , coal , potassium nitrate , diamonds , and a bamboo - like plant , Kirk constructs a makeshift cannon . Spock , impressed by the captain ' s ingenuity , posits that Kirk might be successful if he can complete construction of the cannon before the Gorn closes in for the kill . Moments from a fatal attack , Kirk rips up his own uniform to make a fuse and uses the metallic recording - translating device provided by the Metrons to spark the coal , allowing Kirk to touch off his crude device which incapacitates the Gorn . Kirk has won the contest , but stops short of delivering the fatal stroke to the Gorn captain . He yells out loud to the unseen Metrons that he won ' t kill him and that they will have to find their entertainment elsewhere . The Gorn suddenly disappears and the Metron appears , expressing surprise : their analysis did not prepare them for Kirk ' s demonstration of mercy towards his helpless opponent . The Metron informs Kirk that he is 1 , 500 Earth years old and has returned the Gorn to his ship . The Metron will destroy him for Kirk , if he so chooses . Kirk declines and claims that the Federation and the Gorn can talk their dispute over and perhaps reach an agreement . This also impresses the Metron and theorizes that although Humanity is still half - savage , perhaps in several thousand years it will be civilized enough to be of further interest to the Metrons . Kirk is returned to the " Enterprise " , where he discovers that the ship has been relocated five hundred parsec s away from the Metron solar system . Talking over the incident with the Gorn captain and the Metrons with Spock , Kirk tells his first officer that " " We ' re a most promising species , Mr . Spock , as far as predators go , " " when Spock asks what happened after Kirk fired off his cannon . Spock remarks that he frequently had his doubts about that , but Kirk informs him that in a thousand years or so , Humanity will be able to prove it to the Metrons . " " A thousand years , captain ? , " " Spock inquires . " " Well , that gives us a " little " time , " " Kirk replies as the " Enterprise " heads back to Cestus III . Memorable quotes . " " Doctor , you are a sensualist . " " " " You bet your pointed ears I am . " " " " Like most Humans , I seem to have an instinctive revulsion to reptiles . " " " " This place is a mineralogist ' s dream . " " " " We appeal to you in the name of civilization ! Put a stop to this ! " " " " Your violent intent and actions demonstrate that you are not civilized . " " " " I weary of the chase . Wait for me . I shall be merciful and quick . " " " " Can he do it ? " " " " If he has the time , doctor . If he has the time . " " " " By sparing your helpless enemy who surely would have destroyed you , you demonstrated the advanced trait of mercy . Something we hardly expected . " " " " You are still half savage . But there is hope . " " " " We ' re a most promising species , Mister Spock , as predators go . Did you know that ? " " " " I ' ve frequently had my doubts . " " " " I don ' t . Not anymore . " " Links and references . References . 8th century ; 2279 PL ; 2466 PM ; Archanis ; Arena planet ; asteroid ; azimuth ; " Bones " ; Canopus ; Cestus III ; charcoal ; chef ; chemistry ; club ; coal ; commodore ; communications officer ; deflector screen ; diamond ; diplomat ; disruptor ; Earth ; Earth Observation Outpost ; Earthling ; Federation ; Gorn ; Gorn starship ; grenade ; grenade launcher ; gunnery officer ; gunpowder ; hospitality ; impulse engine ; logic ; Metron ; Milky Way Galaxy ; mineralogist ; ordnance officer ; parsec ; phaser ; photon torpedo ; potassium nitrate ; recording - translating device ; red alert ; sensualism ; shock ; Sirius ; space - normal speed ; Starfleet Command ; sulfur ; tactics officer ; transformer bank ; transporter ; tricorder ; vine ; warp drive