The Robinsons discover that the planet they are on harbors an active volcano. Don and Smith travel in the chariot to plug it with a depth charge. En-route they are captured by a caveman-like tribe who, ironically, are technologically advanced.
The tribespeople believe the volcano is their friend and must not be interfered with. They worship a computer-like machine they have named The Great Protineus. The cavemen think that Don and Smith have contaminated them with their very presence. They place them both in captive quarantine in an underground enclosure.
Don and Smith try to blast their way out but only end up entombing themselves. With dwindling oxygen supplies they believe they have very little time left. In hilarious scenes, especially for viewers who have endured the non-stop animosity between these two characters since pretty much the first episode of Season One, Dr Smith and Don pledge to put all their mutual grievances behind them and emerge as lifelong friends if they can make it out of the collapsed cave deep underground alive.
The robot and The Great Protineus then engage in a series of contests to determine who has the superior powers. When it appears the robot is able to conjure the more impressive feats, the tribes people begin worshipping him instead of The Great Protineus.
While the tribe’s attention is focused on the duel between the two machines, John rescues Smith and Don from the cave. When the volcano threatens to erupt again, John and Will cap it just in time. When the leader of the tribe witnesses the robot’s powers to be superior to those of The Great Protineus, he realizes, after observing the Robinson’s relationship to their robot, machines are designed to serve – not to be worshipped.
Character actor Arthur Batanides (1923 – 2000) played the role of chief of the tribes people, Rongah. Batanides got into acting after performing stand-up routines in front of fellow GI’s in Europe during World War II. He appeared in uncredited roles in both THE TEN COMMANDMENTS (1956) and SPARTICUS (1960).
Later in his career he played the reoccurring role of ‘Mr Kirkland’ in four of the POLICE ACADEMY movies, including POLICE ACADEMY 6: CITY UNDER SIEGE (1989) which was his final film role.