Blessed with astonishing power and grace, Ukrainian dancer Sergei Polunin rocketed to the top of the ballet world. At 19 years old he became the youngest ever principal dancer in London’s Royal Ballet. Two years later, he quit. There was nothing left for him to accomplish, and his pursuit of stardom had torn his family apart and left him feeling hollow. Filmmaker Steven Cantor’s new film documents Polunin’s rise, fall, and redemption. It’s called Dancer, and he joins us Thursday to talk about it.