the episode, Uhura is almost back to normal). To uncover more information, Spock performs a Vulcan mind meld with the machine. He discovers that Nomad collided with a meteor and was severely damaged. It then wandered through space, finally coming into contact and merging with a powerful alien probe called Tan Ru, designed to obtain and sterilize soil samples from other planets. Nomad partially integrated Tan Rus agricultural mission directives, interpreting them to mean "sterilize imperfections". The merging of the two probes imbued Nomad with Tan Rus vast powers, sufficient to destroy life throughout an entire solar system. Kirk compares Nomad's reincarnation to the changeling legend, in which a human child is switched with a fairy child, with the latter assuming the identity of the former. Nomad escapes from its cell, killing two guards who attempt to stop it. The probe makes its way to the engineering deck, where it begins to make adjustments to the engines, accelerating the ship beyond its normal maximum warp speed. As Kirk arrives, Nomad tells him that engine efficiency has been boosted 57%; Kirk orders it to reverse the changes since other structures on the Enterprise cannot handle the faster speed. Nomad complies. Exasperated by Nomad's prejudice toward imperfect "biological units", Kirk points out that its own "Creator" is a biological unit. Nomad responds that it must "reevaluate." Kirk orders the probe back to the brig, and it departs under security guard. Spock then suggests to Kirk that admitting to Nomad that he, "the Creator," is imperfect was probably a mistake. Spock also observes that because Nomad has threatened to return to its "launch point," the Earth and all its inhabitants are now at risk of sterilization. En route to the brig, Nomad kills its two security escorts and heads instead to sickbay. After examining Kirk's medical files and verifying his imperfections as a biological unit, Nomad's "reevaluation" is complete. It proceeds to engineering, incapacitates crew members and shuts down the ship's life-support systems, thus rendering the Enterprise habitable for only a short time longer. Kirk arrives and again confronts the probe, questioning it about its mission. When Nomad declares that its directive to sterilize imperfections allows no exceptions, Kirk points out that Nomad itself is imperfect, since it has mistaken Captain Kirk for its true creator Jackson Roykirk. He then claims that Nomad has committed two other errors, by not discovering its own