The Changeling ( episode ) The " Enterprise " finds an ancient interstellar probe from Earth , missing for 265 years , which has somehow mutated into a powerful and intelligent machine bent on sterilizing entire populations that do not meet its standards of perfection . Summary . Teaser . The is en route to the Malurian star system , investigating a distress call . Lieutenant Uhura has received no response to hail s on any frequency , even after Captain Kirk reminds her of a Federation science team transmitter from Doctor Manway . However , Spock ' s sensor data contains tragic news : although there should be over four billion Malurians there are absolutely no readings of life anywhere in the system . As Kirk and Spock speculate about what could have caused the eradication of life in such a short time , a large bolt of energy comes out of nowhere . Kirk orders red alert , and the object violently impacts upon the " Enterprise " s shields . Act One . The entire crew is hurled around , and when things stabilize , Kirk orders Uhura to inform Starfleet of the apparent disappearance and the attack . Spock reports that the shields will stand only three more such impacts , as they have been reduced by 20 % . The " Enterprise " s shields continue to be battered by repeated attacks . Finally , after the shields are completely gone and a photon torpedo in response has been completely absorbed , Kirk orders Uhura to hail the very small object Spock has identified as the source of attack . The object stops its assault and tries to respond to the hail with an old - style binary code . The crew has some difficulty translating , but eventually succeeds . The object identifies itself as " Nomad " , and its mission as " non - hostile . " As it is only a fraction over one meter in length Kirk has it beamed aboard , if only to prevent it from firing on the ship again . It introduces itself and Kirk remembers the launch of a probe named " Nomad " in the early 2000s , and Spock says it was reported destroyed with no more in the series . Later it is revealed that the object had stopped its assault when it heard Kirk ' s " name " , somehow believing that Kirk is its creator . Act Two . " Nomad " wastes no time investigating the ship , with only Kirk ' s orders preventing it from having free rein . Knowing how powerful it is , and that it stated it was programmed to destroy " biological infestation , " Kirk orders two security guards to watch it at all times , but " Nomad " is able to evade them . Furthermore , it seems highly logic ally - minded and gets confused whenever it encounters something illogical ; when it hears Uhura singing " Beyond Antares " on the bridge from the auxiliary control room , it leaves Lieutenant , who was watching it , and goes to investigate . Meanwhile , Kirk and Spock check the computer on " Nomad " s creation and launch . Originally , " Nomad " was built by Jackson Roykirk for a deep - space extraterrestrial contact mission early in the 21st century , in the year 2002 , but was lost in a meteor shower , where it was presumed destroyed . Somehow , it got a directive to kill , and must have killed the Malurians . " Nomad " arrives on the bridge to question Uhura , and it is unsatisfied with her explanation of the song ' s function and wipes her memory . Scott , seeing this , attempts to save Uhura from the probe , but is thrown clear of " Nomad " , landing near the viewscreen . Upon Dr . McCoy ' s examination of Scott , he declares him dead , to Kirk ' s shock . Act Three . Just after Scott ' s death , " Nomad " announces to Kirk if he wishes to have the " Enterprise " s chief engineer " repaired " . Kirk immediately replies in the affirmative , although McCoy tells him that Scott must be revived soon . Spock has detailed files on Human physiology brought up at his station , which " Nomad " scans . McCoy then leads " Nomad " to sickbay , where the probe instantly revives Scott , who is baffled as to why everyone is looking down at him on a bio - bed . Kirk also orders " Nomad " to help Uhura , but Nomad says it is not possible . McCoy and Nurse Chapel proceed to re - educate her using the computer . This event proves disconcerting to Kirk , who then orders " Nomad " to be guarded and analyzed by Spock . After the analysis and a background check on " Nomad " in the ship ' s data banks , Spock gets enough details through a mind meld with the probe to fill in the blanks . After the meteor collision , " Nomad " was disoriented and wandered through space until coming into contact with " Tan Ru " , an alien probe whose mission was to collect and sterilize soil samples , presumably as a prelude to colonization . The two melded into this new " Nomad " , combining their technology and missions into one extremely powerful probe bent on sterilizing any imperfect lifeform s it encountered , using its own perceptions of perfection ( i . e . itself ) as a measuring stick . As such , it destroyed all life in the Malurian star system but because its original programming was damaged and corrupted in the merger , it erroneously equates Kirk with its creator , not realizing that the two are different people and its creator has been , in fact , dead for centuries . While Kirk and Spock are gone , " Nomad " leaves the confined area and decides to improve the efficiency of engineering , taking the " Enterprise " eventually to warp 10 in the process . Kirk arrives and forces it to stop . Unfortunately , the mind meld and an unintentional admittance from Kirk confirms to " Nomad " that its creator is an imperfect biological entity , and with that knowledge , it leaves on Kirk ' s order to contemplate the new data with two security officers . They deduce it will not obey for long and eventually sterilize Earth . Act Four . En route , " Nomad " instead escapes , killing the two guards , and goes to sickbay to scan Kirk ' s personnel file . McCoy finds Nurse Chapel has been attacked , and signals Kirk and Spock to come to sickbay . They realize " Nomad " is gathering the information they feared . Furthermore , Scott informs them from the bridge that " Nomad " has turned off all life support on the ship . With little time left , Kirk comes to recognize " Nomad " s refabricated mission and takes a gamble to confront it again before it returns to Earth to " sterilize " the planet ' s population . Through a questioning to " Nomad " on its prime directive in engineering , Kirk confirms his suspicions that it must execute it with no exceptions , and then reveals that he indeed is not " Nomad " s creator . He explains that " Nomad " had mistaken himself for Roykirk who is long dead , the two men ' s names being similar , and as such " Nomad " has committed an error ; furthermore , it has compounded that error with two more , specifically failing to realize its mistake and failing to immediately execute its prime directive as a result . This causes " Nomad " to lock up in an irreversible logic loop , its stubborn belief that it is perfect conflicting with the realization that it is in error . Capitalizing on the weakened " Nomad " , Spock and Kirk manage to get it to the transporter room with anti - grav s and have Scott beam it out into space just as it executes its prime function on itself . The explosion is detected near the " Enterprise " and " Nomad " is no more . Later , on the bridge , Spock commends Kirk on his dazzling display of logic that allowed them to defeat " Nomad " . McCoy enters through the turbolift and reports that Uhura is now reading at a college level and should be able to return to duty within the week . Spock laments the loss of " Nomad " , noting that it was a " " remarkable instrument . " " Kirk jokingly wonders what Spock is so upset about , given that the machine considered Kirk to be its " mother " . " " You saw what it did for Scott . What a doctor it would have made . My son , the doctor . Kind of gets you right here , doesn ' t it ? " " Kirk says while pointing to his heart . Memorable quotes . " " This is our point of origin , the star we know as Sol . " " " " You are from the third planet ? " " " " Yes . " " " " A planet with one large natural satellite ? " " " " Yes . " " " " The planet is called Earth ? " " " " Yes . " " " " This is one of your units , creator ? " " " " Yes , he is . " " " " It functions irrationally . " " " " Spock , Bones . Come with – us . " " " " That unit is a woman . " " " " A mass of conflicting impulses . " " " " This unit is different . It is well - ordered . " " " " A man is not just a biological unit that you can patch together . " " " " The ball is bl - u - ee . Bl - u - ey . Bluey ? " " " " The creation of perfection is no error . " " " " You are the Creator . " " " " You ' re wrong ! Jackson Roykirk , your creator , is dead ! You have mistaken me for him , you are in error ! You did not discover your mistake , you have made two errors . You are flawed and imperfect . And you have not corrected by sterilization , you have made three errors ! " " " " My congratulations , captain . A dazzling display of logic . " " " " You didn ' t think I had it in me , did you , Spock ? " " " " No , sir . " " " " It ' s not easy to lose a bright and promising son . . . my son – the doctor . " " Background information . Apocrypha . Tokyopop ' s " : Kakan ni Shinkou " had a story titled " Communications Breakdown " , set after the episode . The story starts with a captain ' s log mentioning that it ' s been twelve days since the encounter with " Nomad " . Links and references . References . 2000s ; analysis sector ; anatomy ; ; antigrav ; antimatter input valve ; Auxiliary Control Room ; ball ; " Beyond Antares " ; binary ; biological unit ( aka " unit " ) ; " Bones " ; brain ; brain damage ; brig ; census ; central nervous system ; ; channel 1 ; Chart 14A ; chief engineer ; college ; condition red ; Creator ; damper ; dog ; Earth ; energy release control ; English language ; evasive maneuvers ; Federation ; Federation science team ; first grade ; flash feed ; force field ; hyperencephalogram ; interfactor ; interplanetary code ; interplanetary war ; interstellar probe ; kilogram ; kilometer ; life support system ; logic ; Luna ; Malurian s ; Malurian population ; Malurian system ; manual override ; memory bank ; Manway ; mathematics ; matter - antimatter propulsion system ; meter ; meteor ; Milky Way Galaxy ; mother ; music ; natural satellite ; neurology ; " Nomad " ; non sequitur ; opinion ; parasitical beings ; personnel file ; physical ; physiology ; polymass ; population ; private transmitter ; prototype ; reader ; reading ; red alert ; ; science team ; screens ; ship ' s translator ; shock ; singing ; Sol ; space happy ; speech ; star chart ; Starfleet Academy ; Starfleet code ; Starfleet Command ; structural integrity ; Swahili language ; Symbalene blood burn ; " Tan Ru " ; tape ; translator computer ; Vulcan mind probe ; woman Library computer references . acquisition sensor ; coupler prediction scanner ; data assimilation digital encoder ; International Designator ; Jupiter ; magnetohydodynamic vernier - pulse ; Mars ; ; Neptune ; Pluto ; regenerative mode emulsifier ; Saturn ; selective amplifier screen ; Sol system ; sperographic analysis computer ; tracking screen ; transmission ; Uranus ; Venus