1970年代传奇摇滚乐手丹尼柯林斯（阿尔·帕西诺 Al Pacino 饰）在经历人生低潮时，经纪人（克里斯托弗·普卢默 Christopher Plummer 饰）发现了一封40年来从未送达的信，这封信居然来自披头士主唱约翰·列侬，在40年前写给当时19岁的他，这让他再度受到启发，毅然决然地离开现在奢华的生活，踏上寻找生命意义的旅程，而他也在这段旅程中收获了真爱和消失已久的创作灵感……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.