Aging 1970s rocker Danny Collins (Al Pacino) cannot give up his hard-living ways – but then his manager, Frank Grubman (Christopher Plummer), uncovers a 40-year-old undelivered letter to him from John Lennon. After reading the letter, Danny decides to change his way of life. He travels to New Jersey to attempt to connect for the first time with his grown son, Tom Donnelly (Bobby Cannavale), whom he sired from a casual relationship with a woman who died 10 years before. Tom has a wife, Samantha (Jennifer Garner) and seven-year old daughter, Hope (Giselle Eisenberg).