Atouk (Ringo Starr) is the leader of a small band of misfit cavemen who are part of a larger community headed by strongman Tonda (John Matuszak). Atouk is madly in love with Tonda’s woman, Lana (Barbara Bach). He even ignores the advances of the lovely Tala (Shelley Long) and sets his mind to finding some way of wooing Lana. During Atouk’s quest for romance, he and his cohorts fend off dinosaurs, indulge in hallucinogens and invent cooking, music and medicine.
A scientifically miniaturized marine unexpectedly finds himself floating around the body of a hypochondriac and trying to outwit saboteurs who want the device that shrank him. Attempts by his colleagues to retrieve the little man – protected inside a tiny submersible – are hampered by the would-be thieves.