The story of boxer Claressa "T-Rex" Shields, who at age 17 won the gold medal in the 165-lb. weight class at the 2012 London Olympics, the first time women boxing was included in the Games. The documentary sheds light on what has not been an easy life. A native of Flint, Mich., Shields has faced poverty and an unstable home life; the latter led her to be taken in by her boxing coach, Jason Crutchfield, and his family.