Sixties City: The Changeling

Voice of Nomad
Vic Perrin

Mr. Singh
Blaisdell Makee

Lt. Carlisle
Arnold Lessing

Following the unexplained deaths of the four billion inhabitants of the Malurian system, the Enterprise has been sent to investigate the cause. It is attacked by a small, incredibly powerful craft that disables the starship's shields. On being contacted it identifies itself as 'Nomad' and beams itself aboard the Enterprise. It quickly comes to the mistaken belief that James T. Kirk is its creator, Jackson Roykirk, and informs him that its mission is to destroy biological infestations.

Spock checks the computer records and concludes that Nomad was originally a craft launched from Earth in the 21st century and that it has, somehow, undergone changes to make it into what it is now. After hearing Uhura singing over the ship's intercom, Nomad seeks her out on the bridge and asks her the purpose of music. On failing to get a satisfactory answer it completely wipes her brain clean of memories.

Scotty, trying to save her, attacks the machine but is killed by some sort of beam with which Nomad protects itself. Kirk requests Nomad to 'repair the Scott unit' which, after accessing the medical databanks, it does, restoring him to perfect health without even touching him. It cannot, however, restore the memories it has wiped from Uhura's brain. Nomad allows Spock to mind-meld with it, revealing that it had been in a collision with an alien space probe called 'Tan Ru'. The two craft were merged into one and their programming became corrupted and intertwined, resulting in it believing that its purpose now is to sterilise imperfection.

Only the fact that it believes Kirk to be its creator has saved the Enterprise crew so far. Kirk tries to reason with the machine, which insists that biological 'units' are inferior and must be sterilised. He tells Nomad that it was created by an 'imperfect' biological unit, causing the machine to start re-evaluating the situation. After assessing Kirk's personnel files in the ship's computer it proceeds to shut down the Enterprise life support systems. Nomad refuses Kirk's order to repair them and tells him that it will return to Earth and sterilise all imperfection on the planet.

Seizing on a slim chance, Kirk tells Nomad that it has made an error itself in believing that he was the creator, and a second error in not 'sterilising' after the first error. The machine 'hangs' while processing this anomaly, giving Kirk and Spock the opportunity to fix antigrav units to it, taking it to the transporter room and beaming it into deep space before its internal conflicts cause it to explode. Starfleet teaching techniques ensure that Uhura is brought back to normal in a fairly short space of time.