As a boy, Bobby Darin (Kevin Spacey) nearly died from rheumatic fever. While it left him with a weakened heart, it didn't weaken his desire to become the most popular singer in the country. Knowing that he's living on borrowed time, Bobby works nonstop to conquer the pop and jazz worlds with hits like "Splish Splash" and "Mack the Knife." But as the '60s come into full swing, Bobby sees his style of singing fall out of favor, and his marriage to actress Sandra Dee (Kate Bosworth) suffer.