The film traces the tragic-heroic life of the late teen singing idol, Bobby Darin. Born with a rare heart condition that was to limit his life span to merely 16 years, Darin survived to age 37 when he was felled by a blood infection contracted during open heart surgery. Darin produced such hit songs as "Splish Splash," "Mack the Knife' and "Beyond the Sea".

For BOBBY DARIN (Kevin Spacey), performing was his life. It kept his heart beating. He came alive onstage, even when he was near collapse offstage. In BEYOND THE SEA, Bobby tells us his own story, in his last great performance.

With a heart damaged by rheumatic fever, Walden Robert Cassotto - Little BOBBY (William Ullrich) isn't supposed to live to see age 15. But when his mother POLLY (Brenda Blethyn) shows him the happiness that comes with music, Bobby finds the inspirationi he needs to stay alive. Making music opens a world beyond sickness, where prodigious talent, drive and imagination can overcome a faulty heart. With the help and support of his devoted family - Polly, his older sister NINA (Caroline Aaron) and Nina's husband CHARLIE (Bob Hoskins) - Bobby will become a star.

And so he does. The sickly boy from the Bronx reinvents himself as Bobby Darin, a magnetic entertainer who becomes a rock and roll sensation with "Splish Splash" and emerges a full-fledged star with "Mack the Knife." Working with his best friend-turned-manager, STEVE BLAUNER (John Goodman), Bobby charts his own stubbornly eclectic musical path, writing original songs and performing in a range of genres. Turning his sights beyond music, Bobby launches a movie career and marries America's favorite young star, SANDRA DEE (Kate Bosworth). But Bobby's relentless professional ambition has begun to poison his private life, and the late 60s find him isolated, confused and directionless. In the end, with his childhood illness finally catching up with him, Bobby must look to his friend, family and extraordinary talent to quell his demons and accept who he is and what his life has meant.