The 2015 Reebok CrossFit Games were a 5 day, 13 event, grueling test to find the fittest male and female on earth. "Fittest on Earth" follows the dramatic story of the top athletes who qualified and competed. A behind the scenes look into what it takes to be among the worlds elite athletes. Athletes find out which events they are going to test themselves weeks, sometimes days and even minutes before they take the competition floor. The film follows 8 of the worlds top athletes as they compete.