|Principal Cast:||John Robinson (Guy Williams)|
|Supporting Cast:||James Gosa as Gilt Proto|
|Preceded By:||The Anti-Matter Man|
|Followed By:||Princess of Space|
Shapeless aliens imprison the Robinsons and make themselves into their doubles (boy, they sure had a lot of problems with imposters), and then hijack the Jupiter 2, planning to go back and conquer the Earth (again! <sigh>) . They reprogram the Robot to help them. Will and Smith escape, capture their doubles, and replace them on the journey, in an attempt to stop them.