The beginning of the third season finds the Robinsons having to quickly leave the planet they are on, which is a similar plot to the beginning of the second season.  Once in space, the robot is swept overboard and has to be rescued.  Then the Robinsons find a prison ship filled with cryogenically preserved prisoners.  The prisoners have been interred past their normal sentences due to a malfunctioning timepiece on the prison ship.  Professor Robinson repairs the timepiece and frees the prisoners.  Robby the Robot makes another appearance, threatening Professor Robinson and Major West.
               
              
                Casts: 
                Guy Williams, June Lockhart, Mark Goddard, Marta Kristen, Angela Cartwright, Bill Mumy, Jonathan Harris, Dick Tufeld, Bob May