Little Johnny (Gregory Moffett) is playing in the Californian countryside when he meets little Carla (Pamela Paulson) who wants to play "house" with him, but he is more interested in pointing his toy ray gun at her and trying to disintegrate her. He then moves on to the nearby cave, where he meets two archaeologists, the Professor (John Mylong) and Roy (George Nader), who humour him about allowing him to assist in their studies, but suddenly there is a lightning bolt from the blue which strikes Johnny down where he stands. And then the dinosaurs start fighting...
Wait a minute, what dinosaurs? There weren't any dinosaurs in California in 1953, but you're reckoning without the power of director Phil Tucker's stock footage, which appears to have been inserted with little regard as to how relevant it was. Besides, the addition of dinosaurs to any movie can only be an improvement, right? Sadly, Robot Monster is considered one of the worst films ever made, although as with many such works awarded such a prestigious title, there is something weirdly entertaining about its thorough wretchedness.
The most notorious element is the villain, the imaginatively named Ro-Man, not Roman, he doesn't dress in a toga, but Ro-Man, who appears to be a man in a portly gorilla costume wearing a space helmet (some say it's a diving helmet). This is because he is a man in a portly gorilla costume wearing a space helmet, and despite his apparently massive powers, there's something rather forlorn about watching actor George Barrows trudging through the landscape from afar, accompanied by music from Elmer Bernstein (hey, he had to start somewhere) which overstates his menace to somewhat ridiculous degrees.
The whole thing is ridiculous, but the plot reveals itself to be surprisingly bleak, even if Wyott Ordung's script implements the most hackneyed ending to science fiction films ever, although it was pulled off in its contemporary Invaders from Mars. That ending may be reassuring, until the final shot at least, but the rest of this sees the entire human, sorry, Hu-Man race destroyed except for Johnny, his parents who now feature the Professor as his father (can you guess why?), Roy, Carla and Johnny's (much) older sister Alice (Claudia Barrett). Now they must fight for suvival, and learn to get along with each other, naturally.
More lunacies here include Ro-Man living in the cave as his base of operations, the familiar Bronson Canyon cave from a million such productions, but having an unexplained bubble blowing machine there. He also has intense conversations with the suspiciously identical-looking Great One, his boss, and has to wrestle with his conscience with when he falls for Alice (we're not sure what he plans to do to her, but he does try to rip her clothes off - steady!). Classic dialogue of the "I cannot - yet I must. How do you calculate that? At what point on the graph do "must" and "cannot" meet? Yet I must - but I cannot!" variety abounds, but what you take away from this sorry fiasco is that desire to see all of the world devastated; rumour had it that Tucker attempted suicide after this film flopped, and you could see Robot Monster as the work of a depressive. In its naive way, it's a pathetic and dejected little film, even if it does raise a number of unintended laughs.