When accountant, Jenna Stone, unexpectedly becomes involved in an underground female fight competition with an unlikely group of women, including her therapist, the women are forced to come together to take down the fight promoter who has started to exploit and abuse the fighters. They do this by creating their own safe and professional female fighting organization; Sister of the Fight. The path to their first event is not an easy one, and involves a kidnapping, attempted murder, and a new relationship that Jenna will struggle to maintain as she works through her own propensity to "act out," and to let go of something that she calls, Mental Burn.