Will and Doctor Smith are out and about and a swift gun named Xeno who is on the run from the law and happens to be a exact double for Dr. Smith trades places with him allowing the real Dr. Smith to be arrested in his place.

The mysterious Saticon's make a offer to the Robinsons to buy the robot. The offer is turned down and then in the middle of the night the robot disappears. Later it is discovered that the Saticon's are more than they seem.