Mariana van Zeller explores the fastest growing sport in America - Mixed Martial Arts (MMA). MMA is now a billion-dollar industry, watched by millions on national TV. But increasingly, amateurs are stepping onto the mat and drawing blood. Mariana meets male and female cage fighters to understand why they love this violent sport. And she spends time in a church run by "The Fight Pastor," who ministers a flock of young men who fight for Jesus.