In this sci-fi fantasy, based on a Jules Verne story, two 18th-century men are preparing for a duel when they find themselves caught in the tremendous tailwind of a passing comet. They get sucked onto the comet's head where they find a strange world inhabited by dinosaurs and cave men. The rivals are forced to split up. When they see each other again, each has become the leader of rival cave-man clans during a war. Peace is restored when the heroes each fall for a woman belonging to the other's clan.