In the final episode of Lost in Space's second season, Penny (Angela Cartwright) saves the life of an alien named Arcon (John Carradine), who entrusts her with a valuable amulet. Not long afterward, a trio of sinster space thugs show up, demanding that Penny give up the amulet, or else the rest of her family will die a horrible death. Making Penny's choice all the more difficult is the fact that the amulet holds the power to destroy the universe. (Trivia note: the costumes worn by the villainous "Saticons" were previously seen in the episode "Wreck of the Robot").
by Hal Erickson synopsis