Dr. Alan Feinstone is a successful dentist. However, everything changes on the day of his wedding anniversary, when he discovers his wife Brooke is cheating on him with the poolman, Matt. After they finish, Alan retrieves his pistol and follows Matt in his car. He is led to Paula Roberts's house, a friend of Brooke's. Alan invents a story about a surprise party for Brooke and watches Paula invite Matt inside. Paula's dog attacks Alan, and he shoots it in self-defense. After returning to his car, he drives to work.