An ageing hard-living 1970s rock star decides to change his life when he discovers a 40-year-old undelivered letter written to him by John Lennon.

Cal Weaver is living the American dream. He has a good job, a beautiful house, great children and a beautiful wife, named Emily. Cal's seemingly perfect life unravels, however, when he learns that Emily has been unfaithful and wants a divorce. Over 40 and suddenly single, Cal is adrift in the fickle world of dating. Enter, Jacob Palmer, a self-styled player who takes Cal under his wing and teaches him how to be a hit with the ladies.