Frank Castle is a man who has seen too much death in his life, first as a Delta Force Op and later as an FBI special agent. He has managed to beat considerable odds, and is finally moving out of the field and into a normal life with his wife and son. On his final assignment, Castle plays his undercover role perfectly, but the operation spins out of control. This places the FBI on the wrong side of Tampa businessman Howard Saint and his glamorous wife Livia. Notwithstanding their glossy social profile, the Saints are no genteel Florida couple; behind their copious wealth are violent beginnings, underworld ties - and a chilling capacity for brutality. Castle's worst nightmare is about to come true, as Howard Saint and his lieutenants unleash hell at the Castle family reunion. But Castle, to his everlasting torment, survives. Drawing upon all he has learned in 20 years, Castle sets in motion a brilliant plan to punish the murderers. He takes up residence among in a dilapidated tenement building on Tampa's industrial waterfront, where his fellow tenants include Joan, a waitress at a nearby diner who is trying to put her life back on track. Castle's neighbors become his last link to the idea of human community and warmth. It is this makeshift family - forgotten men and women with no one to protect them - who enable Castle to find the one thing he least expects: redemption.