Michael and Cathy a loving couple decide to take a summer vacation on a remote island. They soon discover that the world they know can become broader. They find themselves surrounded by nudists on a nude beach, and although unsure at first they become a part of the society around them. The trip away from home takes Cathy into a more seductive side, and Michael and her start experimenting with their sexual fantasies.
Michael has been faithful to Cathy thus far, but he is smitten with a native islander Lina. Michael starts having fantasies about Lina, and when Cathy is not around he develops a relationship with her. Lina and Michael's relationship gradually leads to an affair. Cathy becomes alarmed when she sees Michael's reaction around Lina, and Michael admits he and Lina are having an affair. Surprisingly, Cathy tells Michael to just get it over with, and he agrees but the affair continues to loom forward. Cathy becomes distraught and attempts to find a young man to get back at Michael, but she succumbs to her guilt and does not go through with it.
Cathy can no longer take the affair and confronts Lina. However, to Cathy's surprise she and Lina have a lot in common. The two are fascinated with each others work, and they develop a friendship. The friendship eventually leads to a threesome, and everyone is enjoying themselves and the vacation. Cathy's mother makes an unexpected visit, and humor is added when she is not accustomed to the islanders way.
Lina fears that the American couple will leave her, and she can't bear the idea of getting hurt. Lina disappears and meets a new young man Jan Tolin. Cathy and Michael are distraught about Lina's disappearance and look for her. They do not find her and decide to shorten their vacation and return home. Lina learns of their departure and finds them at the airport. They all enjoy the vacation together.