Underdog is a film about the triumph of the spirit and hope. Sam is a young foster woman with a traumatic, criminal past. As she is recovering from a near fatal drug overdose, she is introduced to Donovan, an older boxing coach, who has is own addiction issues. The two form a bond of trust she respects. Through Donovan's mentoring and training, and Sam's determination and courage, Sam takes us on her journey as she fights her way toward the MMA title, while her and Donovan's past ghosts attempt to derail their championship hunt. Can they tame their inner demons and continue to fight, win or lose, never abandoning hope for a better life?