Rather than providing a straightforward biography, the film weaves fantasy sequences with scenes containing somewhat fictionalized accounts of events in Darin's life, and throughout it, the adult singer interacts with his younger self. It chronicles his determination to rise from his working-class roots as Walden Robert Cassotto, a frail The Bronx boy plagued by multiple bouts of rheumatic fever, and become a singer more famous than Frank Sinatra. To achieve that goal, he forms a band and struggles to find gigs at any nightclub that will hire him.