Full story
Frank Castle is an FBI agent in Tampa working his last undercover job before retirement. He poses as an arms dealer in a sting that goes wrong: Bobby Saint, son of mob boss Howard Saint, dies in the shootout. Howard finds out who the undercover agent was. His wife, Livia, demands that no one in Castle's family be left alive.
Castle is at a family reunion in Puerto Rico with his wife, Maria, his son, Will, and his parents. Saint's men, led by Quentin Glass, the mob boss's right hand, and Saint's son John, crash the party and kill everyone. Castle is shot, left on a pier and blown up. He survives, washes up near a local fisherman, Candelaria, and slowly recovers.
Five months later, Castle returns to Tampa with an arsenal and moves into a run-down building. His neighbors are three loners: Joan, a waitress who escaped abusive boyfriends; Bumpo, a big, gentle guy; and Dave, covered in piercings. Castle wants revenge, but planned. With help from Mickey Duka, one of Saint's men who feeds him information, he starts hitting the mob boss's money and sowing distrust inside the organization.
Saint sends killers after him. A gunman who sings in a diner ambushes him on the highway and ends up dead. Next comes the Russian, a giant bruiser who wrecks Castle's apartment in a long fight until he's thrown down the stairs. Glass tortures Dave, who won't give up Castle. Meanwhile, Castle learns Glass's secret and sets up a frame: he makes Saint believe Livia is cheating on him with Glass himself. Saint stabs Glass to death and throws Livia in front of a train.
On the final night, Castle storms Saint's club and kills all his men, John included. Saint escapes wounded and Castle finds him in the parking lot. Before the end, he tells Saint how he was played into killing his best friend and his wife. Castle drags him tied to a car, and a chain of explosions across the lot forms the shape of a skull. Alone, he thinks about taking his own life, but a memory of Maria stops him. He leaves money for his neighbors and, on the Sunshine Skyway Bridge, takes the name the Punisher, vowing to punish anyone who harms the innocent.