An American widower and his 18-year-old daughter live on a Caribbean houseboat. Romance and adventure ensue when they invite the bored nephew of a millionaire to leave his uncle's yacht and stay with them. Though there is an immediate spark between the girl and her new friend, romance is delayed by the arrival of the nephew's former business partner. Together, the two young men invest in an underwater treasure-hunting expedition that unfortunately only brings up a few skeletons. The disappointed nephew returns to his uncle's yacht and there realizes that he is in love with the girl. He returns to ask for the girl's hand. Her father is delighted, leaves the newlyweds to their honeymoon and sails his houseboat to a new place.