In Cambridge, software engineer Peter (Liam Neeson) and shoe designer Lisa are successful in their careers and have been happily married for twenty-five years. They have an adult daughter, Abigail, and Lisa frequently travels to Milano to do business with the Gianni & Gianni Company. When Lisa is gone, Peter finds a message in her cell phone and decides to snoop her e-mails and discovers in a secret folder named Love that she had a lover, Ralph. Peter travels to Milano and stalks Ralph; he finds that the man plays chess in a bar. Peter gets close to Ralph and discusses his relationship with Lisa without knowing that he is her husband.