Synopsis by Hal Erickson
Season Three of Lost in Space begins as the Robinson family--together with pilot Don West (Mark Goddard) and cowardly stowaway Dr. Smith (Jonathan Harris)--once again exiting a doomed planet and resuming their mission to Alpha Centauri. Once they've safely escaped collision with a comet, the residents of the Jupiter 2 space vessel comes across a new peril in the form of a computer-operated prison ship, carrying scores of criminals in suspended animation. Accidentally releasing one of the prisoners, Dr. Smith also triggers a series of life-threatening disasters. Watch for Robby the Robot of Forbidden Planet fame in a "cameo" role.