AllMovie

Injured after falling down a hole in a cave, John (Guy Williams) awakens to find himself a changed man. Specifically, the spirit of the centuries-old alien warrior Canto now possesses John's body and a good portion of his mind--a portion which increases every time John falls asleep. Thus enslaved by Canto, John imprisons the rest of his family and prepares to murder his own son Will (Bill Mumy)! Listen as the Robot sums up the cowardice of Dr. Smith (Jonathan Harris) by paraphrasing "The Prisoner of Zenda" in this, the final episode of Lost in Space's first season, and the last one filmed in black and white.