Roller derby is the fastest growing (and, arguably, most entertaining) women's sport in the world. In Austin, Texas, it's the end of season championship bout and the undefeated Cherry Bombs are taking on the Hellcats. Meet the brilliantly named players (Curly Suicide, Miss Amerikill, Rocky Casbah...), get a lesson in the rules (despite appearances, there are rules), and witness the thrills and (eye-wateringly painful) spills of derby at its best.