Lost in Space (1965)

Episode Overview

Dr. Smith, Will, and the Robot stumble upon an ancient harp hidden beneath a carved rock. They soon learn that playing the correct melody opens a gateway to another realm. Upon entering, Dr. Smith encounters an alien who mistakenly believes he is the devil and thinks the place is Hell. When the alien arrives on their planet, Dr. Smith becomes terrified. Meanwhile, Judy strikes up a friendship with the alien and is accidentally transported to the other world. It falls on Don and John to rescue her, leading Dr. Smith to realize that this realm is not Hell, but rather a prison for a criminal.