A group of rich Italians head out on a yachting trip to a deserted volcanic
island in the Mediterranean. When they are about to leave the island, they
find Anna, the main character up to this point, has gone missing. Sandro,
Anna's boyfriend, and Claudia, Anna's friend, try without success to find her.
While looking for the missing friend, Claudia and Sandro develop an attraction
for each other. When they get back to land, they continue the search with no
success. Sandro and Claudia proceed to become lovers, and all but forget
about the missing Anna.