Billy Moore, a young British boxer and troubled heroin addict, is arrested in
Thailand and charged with possession of stolen goods and a firearm. Incarcerated in
Klong Prem prison, he is quickly subjected to the horrors of Thai prison life, including being moved into a crowded cell ruled by cell leader Keng, being forced to sleep next to a corpse and witnessing at knifepoint the rape of a fellow inmate. His interactions with the other prisoners and staff are tense; at one point, he goes into a violent frenzy and bites a corrections officer's neck for being refused painkillers. After his punishment, Billy attempts to befriend a transgender prisoner named Fame. Life in prison worsens for Billy and he retreats into heavy drug abuse. He subsequently beats two Muslim chefs close to death after being bribed with
ya ba by a corrupt prison officer. Billy's mental health ultimately deteriorates and he attempts suicide by slitting his wrist with a
shiv, though he survives after an inmate saves his life. Driven by a desperate need to fight and battle his demons, Billy eventually joins the boxing team with the help of Fame, with whom he becomes intimate with. He quickly adapts to the art of
Muay Thai, winning his first bout in a close, hard-fought battle. Impressed by his performance, the prison warden, Preecha, transfers him to the boxing team cell, becoming the first foreigner to compete in the national Muay Thai tournament and represent the prison. He soon develops a camaraderie with the other boxers and receives a
Sak Yant on his back. However, he is ambushed by Keng and his gang, who threaten him with a
pin prick attack if he loses. Worse, it emerges that Billy is suffering from a hernia caused by his drug abuse and any further damage could result in severe internal bleeding. Nevertheless, he still wants to compete. The resulting match is gruelling, with Billy taking multiple shots to the stomach and being fouled by his opponent. However, he manages to knock his opponent out with a spinning back elbow. Despite his victory, the physical trauma is too much, and he ends up vomiting blood and passing out. Billy is quickly rushed to a hospital outside of prison grounds. After waking up, he sneaks out of the building and wanders into the city, but soon reconsiders and returns unnoticed. After being transferred to another ward, he meets his father (played by the real Billy Moore) and the two men exchange a solemn smile. The closing titles reveal that, after serving three years, Billy Moore was transferred to a UK prison and released on amnesty by the
King of Thailand in October 2010. Since his release, he has devoted his life to helping other addicts and maintaining his own recovery. ==Cast==