The Devil ' s Isle of Space " Prisoners on the planet of the condemned sentence Captain Kirk to share their fate ! " Summary . The asteroid s ahead of the starship " Enterprise " are glowing , like nothing the crew has ever seen before . Captain Kirk tells the navigator to set a course to the nearest glowing planet so that they can investigate . Just as they are preparing a landing party , the ship is hit with atmospheric turbulence . Kirk orders the infra - red periscope raised to see what is outside and discovers that they ' ve in an electronic field shielding the planet . The ship is immobilized , and the landing party beam s down to the planet to discover the source . On the planet , the party discovers large supply dispensing machines , one for food , another for clothing . As they investigate , they are set upon by a group of aliens , but a parlay ensues and Kirk discovers that the aliens , led by Targu , were marooned a year before when their freighter crashed . However , Targu knows nothing about the electronic field . The party sets out and eventually discovers a crashed ship , but do not recognize the controls within . They radio their discovery to Spock and he notes that the ship is not a cargo ship . As they discuss this , another alien arrives and introduces himself as Lara , telling them that Targu is a bad man and a liar . Lara informs them that they are all members of what are known as " the Condemned " , convicts from their home planet . The convicts are gathered at the rocketport , put into missiles , and fired at the glowing planets in the asteroid belt where they wait for their sentence to be carried out – execution . Meanwhile , Targu and his men have spotted Lara talking to Kirk and they round up the others and prepare to attack , unless Targu can talk their way out of things . Targu throws his weapon at Lara , knocking him out , and begins to talk . As Kirk accedes to the idea of further talks , Targu and his men attack , surprising the " Enterprise " team . On board the ship , Spock and Scotty free the starship by flooding the area with counter energy . That action cuts a hole through the force field and the with the " Enterprise " s rockets on full , the ship is free ! However , when they do so , the needle on the infra - red seismograph jumped , giving a critical reading . They get in touch with Kirk and prepare to beam them up , however Targu and his men entrap the landing party in a net , meaning that if Spock beams them up , he will bring the aliens with him . Meanwhile , Spock discovers that the heart of the glowing asteroid is a " " molten ball of fire " " , and that it will supernova within 24 hours . It appears that this is the method of execution for the criminals , and why they did not know the time or date of their executions . Targu explains their story and expands on Lara ' s details . Targu also tells Kirk how he came to be the leader , letting Kirk know what kind of creature he really is . Targu contacts the " Enterprise " with Kirk ' s communicator and demands that Spock beam him and his trusted men off the asteroid . Spock refuses , insisting that he only takes orders from Kirk . Targu gives the radio to Kirk and Kirk tells Spock to take command of the " Enterprise " , and to take the ship as far from the asteroid as possible . On board the ship , the crew is dismayed , telling Spock that he can ' t leave the Captain there to die . Spock tells them that he must obey the order , but is free to ignore the second , since he is now Captain , not Kirk . He and Scotty go to work on some quick plans to save the Captain and the other members of the landing party . That night , as Kirk and the others wait for their doom , they spot a rocket trail – another rocket of the condemned coming to the asteroid . Targu and his men race toward the landing site to take control , as per usual . The rocket comes down awkwardly , crashing through prisoner huts , but Targu is undeterred , only interested in the food dispensers . The door opens , and Spock has sent Scotty down with a raiding party to free Kirk and the others . Spock beams the raiding and landing parties up and puts the rockets on full , taking the " Enterprise " away from the asteroid . Kirk confronts Spock , telling him that he had disobeyed a direct order , but Spock defers to Scotty and Dr . McCoy on the matter , noting that he enjoys being Captain so much that he might never turn command of the vessel back over to Kirk . As they talk , the asteroid suddenly explodes , but the " Enterprise " is undamaged by the explosion and heads off to her next mission . Memorable quotes . " " Ready to teleport you and your party back to the " Enterprise " , Captain Kirk ! " " " No " , Mr . Spock ! You ' ll bring back some undesirables with us ! If these creatures get aboard , they could " doom " the " Enterprise " ! We ' ll just have to fight our way out of this spot ! " " " " Howling comets ! " " " " Don ' t attack unless I give the word ! Maybe I can still " talk " our way out of this ! " " " " Captain Kirk ! I - I ' ve found the problem on your prison planet ! Its heart is a molten ball of fire ! . . . An internal volcano that will blow the planet into a " super nova " within " twenty - four hours " ! " " " " You heard the captain ' s order , gentlemen ! On the other hand , you " also " heard the captain give me command of the ship " prior " to that ! So technically , I am not bound by that order ! " " " " Spock , your Vulcan logic wins again ! " " " " Shades of Pluto ! I think I have the answer ! " "