A very young Ornella Muti plays a rich girl who falls for an older hippie boy. Her parents don't approve and try to stop her from seeing him so they run away to a villa (Her parents') by the sea. Later they are shipwrecked on a deserted island. The plot focuses on the efforts of the police to figure out where the girl is, which is set against the developing relationship between the two young people.
An alien race sends cyborgs — made to look like the son of a famous scientist, whom they killed when he landed on their planet — to Earth to help pave the way for an invasion.