Set in London, it is the story of Charles, a successful but rather stuffy businessman, who meets and marries Belinda, a free-spirited American woman. After a time, he believes she is having an affair because she spends long hours away from home during the day. Charles hires a private detective to follow his wife. Belinda becomes aware that she is being followed, and the detective realises she has found out. However rather than abandoning the case, the detective begins an elaborate game of cat and mouse with the complicity of the wife. The detective finally informs Charles that his wife never had an affair, and merely goes on solitary exploratory walks around the city. The husband realises he has been neglectful and made his wife unhappy. He joins the game of following his wife as an adventure.
