Frank Castle (TOM JANE) is a former Delta Force op and current FBI agent who's looking forward to his retirement with wife Maria (SAMANTHA MATHIS) and young son Will (MARCUS JOHNS).
Yet, the inadvertent death of Bobby Saint (JAMES CARPINELLO) on an undercover assignment has left Frank a marked man. The victim's father, Tampa businessman and crime boss Howard Saint (JOHN TRAVOLTA) wants Frank's blood, while his socialite wife Livia Saint (LAURA HARRING) demands that their vengeance go one step farther. Accordingly, she orders Howard's right-hand man, Quentin Glass (WILL PATTON), not only to kill Frank, but his entire immediate and extended family as well.
Thus, at a Castle family reunion in Puerto Rico, Saint's men massacre Frank's entire family -- including his father Frank Castle Sr. (ROY SCHEIDER) -- believing they've killed him as well. Yet, he barely survives the attack and takes months to recuperate. After returning to the States, Frank takes up residence in a low-end apartment where his neighbors -- the heavily pierced Dave (BEN FOSTER), cook wannabe Mr. Bumpo (JOHN PINETTE) and ex-addict Joan (REBECCA ROMIJN-STAMOS) -- wonder who he is and what he's up to.
As they eventually crack his toughened social shell, they soon discover themselves in a dangerous world where Frank plots to get revenge. Whether it's manipulating Saint's own men -- such as Quentin, lowly goon Micky Ducka (EDDIE JEMISON) and other son John Saint (JAMES CARPINELLO) -- or outright attacking those who wronged him, Frank is determined not to stop until everyone who's responsible is dead.