The film opens during Mark Kerr’s dominant run in late-1990s no-holds-barred tournaments. Despite crushing his opponents, Kerr endures constant physical agony, relying on heavy painkiller injections to step into the ring. Back home in Phoenix, his relationship with Dawn becomes increasingly turbulent, fueled by volatility and emotional isolation.
Kerr travels to Tokyo to compete in PRIDE FC. His streak comes to a crashing halt when he suffers his first brutal defeat against Ukrainian striker Igor Vovchanchyn. Devastated and spiritually adrift, Kerr spirals into deeper substance abuse, culminating in a near-fatal overdose in a hotel room. He is rushed to the hospital and survives.
His trainer Mark Coleman confronts Kerr with tough love, pushing him into rehabilitation. Kerr gets sober, but his newfound clarity alienates Dawn, who struggles with his sober, altered disposition. Kerr returns to train for a comeback, but the story avoids a triumphant fairytale victory. Instead, Kerr enters his subsequent matches clear-eyed, accepting his physical limitations and realizing that survival, sobriety, and self-acceptance outweigh the fleeting high of an undefeated record.