 High-flying tycoon Sir Philip Ashlow (Granger), his neglected wife, Lady Susan Ashlow (Gardner) and his best friend, pettifogger civil servant Henry Brittingham-Brett (Niven), are shipwrecked on a desert island.Susan feels neglected and has been trying to make Philip jealous by demonstrating a romantic interest in Henry, who begins taking her seriously.Now that they are alone on the island, Philip constructs a large hut for his wife and himself and a little hut for Henry, but before long Henry is suggesting they share not only food and water but Susan as well.