AllMovie

Myko (Mike Kellin), the manager of an intergalactic gladiator show, arranges a boxing match between Dr. Smith (Jonathan Harris) and the midget Geoo (Harry Monty). Believing that he'll receive a huge sum of money and a trip back home if he wins, Smith accepts the challenge--little knowing that the match is actually part of a wide-ranging scheme to conquer the earth. It falls to John Robinson (Guy Williams) to take Smith's place in the ring when it becomes obvious that the outcome of the bout has been "fixed" and that the Robinsons are slated for destruction.