Billy Crudup plays Sam, a former high-profile advertising executive whose life is torn apart by the sudden death of his son. Living off the grid on a docked sailboat, he wastes away his days while drowning his pain in alcohol. When Sam discovers a box filled with his son's demo tapes and lyrics, his own child’s musical talent is a revelation for him, a grieving father who felt he’d been absent from his son’s life. Communing with his deceased son’s dashed dreams, Sam learns each song and eventually musters the will to perform one at a local bar. When Quentin (Yelchin), a young musician in the audience, is captivated by the song, the unlikely duo forms a rock band that becomes surprisingly popular and revitalizes both of their lives.