When we first see him, Hank Grotowski (Billy Bob Thornton) is a spiritually comatose corrections officer who seems to have inherited his bigotry, like his line of work, from his father, Buck (Peter Boyle). A housebound invalid, Buck gripes bitterly when he sees a couple of black children stroll across the lawn to pay a visit to Hank's son Sonny (Heath Ledger), and grumbles that there once was a time when colored people "knew their place." Hank compliantly scares the children off with a rifle.

But away from home, Hank's actions are governed by a code of decency that doesn't recognize racial boundaries. The first act of Monster's Ball follows Hank and his colleagues as they prepare for the execution of Lawrence Musgrove (Sean Combs), a convicted cop killer who has run out of appeals. Hank does all he can to ensure that this black man can face his death with dignity.

The exact nature of Lawrence's crime is never spelled out. All we know about him is that he has a young son, Tyrell (Coronji Calhoun), who has inherited his father's love of drawing, and a wife, Leticia (Halle Berry), who wants nothing to do with him. Leticia's life is a mess. Her landlord has posted an eviction notice to her door, her car breaks down, and her boss fires her for being late for work.