An aging rock star decides to change his life when he discovers a 40-year-old letter written to him by John Lennon.

Inspired by a true story, Al Pacino stars as aging 1970s rocker Danny Collins, who can't give up his hard-living ways. But when his manager (Christopher Plummer) uncovers a 40 year-old undelivered letter written to him by John Lennon, he decides to change course and embarks on a heartfelt journey to rediscover his family, find true love and begin a second act.

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). Seeking a new start, Danny forswears touring and checks into a Hilton hotel in New Jersey, much to the delight of the young staff. He begins to woo the hotel manager, Mary (Annette Bening).