When she was 13, up-and-coming pro surfer Bethany Hamilton lost her left arm in a shark attack. That’s just the beginning of her story. Bethany bounced back a month later and today is one of the best surfers in the world. There’s a new documentary about her story, “Bethany Hamilton: Unstoppable,” that hits theaters July 12th. The film’s director, Aaron Lieber, has found a niche making films about female surfers and was committed to telling Bethany's whole story in her own voice.