Double, Double (Star Trek)
On a routine exploratory mission, the starship U.S.S.Hoodpicks up a distress signal from a research expedition though lost long ago, the expedition of Dr. Roger Korby, one of the centuries' greatest scientific minds. Korby himself is dead, it seems, but his colleagues have made a most incredible discovery,  a discovery they insist theHood's captain see for himself. Reluctantly, the captain agrees to beam down.Meanwhile, the crew of theEnterpriseTMbegins long-overdue shore leave on Tranquility Seven. James T. Kirk is looking forward to a few days of rest and relaxation, until what seems like a bizarre case of mistaken identity plunges Kirk into a whirlpool of mayhem and murder, and puts an inhuman stranger with his memories and abilities in command of theEnterprise.