AllMovie

After coming into contact with an uncharted planet, a series of mysterious disappearances begins to decimate the crew of the starship Enterprise in this installment of the 1960s science fiction television series. The rash of disappearances begins after a landing party explores the planet Scalos, causing much puzzlement for the Enterprise officers. Kirk becomes privy to the answer when he himself vanishes, however. He finds that he and the other missing crew members have been kidnapped by the Scalosians, an alien species that closely resembles humans but moves at a speed undetectable to human senses. Having been accelerated himself, the newly invisible Kirk must find a way to communicate his discovery to the others and save the Enterprise.