Paul Kersey, portrayed by Bruce Willis, is a dedicated trauma surgeon residing in Chicago with his wife, Lucy, and their college-bound daughter, Jordan. Their lives take a tragic turn during a seemingly normal lunch when Paul's brother, Frank, asks him for a loan to settle a debt, to which Paul reluctantly agrees. This seemingly small favor leads to dire consequences when a valet named Miguel, excited by the news of Paul's financial support, deceitfully photographs the family's address.
That fateful evening, while Paul is at work, three masked intruders break into their home. In a horrifying turn of events, both [Jordan] and [Lucy] are shot; Paul receives the devastating news at the hospital that he has lost Lucy, and Jordan is left in a coma. Among the investigating officers is Detective Kevin Raines, who soon realizes the gravity of the situation.
Fueled by rage and frustration over the police's inability to apprehend the perpetrators, Paul turns into a vigilante, taking to the treacherous streets under the guise of the "Grim Reaper." When a wounded gang member arrives at the hospital, Paul seizes the opportunity to steal the man's weapon, thwarting a carjacking in the process, which leads to a viral video of his heroic act. His quest for justice intensifies when he finds his watch on Miguel after the latter is hospitalized.
In a brutal twist, Paul ensures Miguel's demise, forcing a doctor to administer fatal electric shocks. Driven by relentless vengeance, he discovers a lead through a text on Miguel's phone, which leads him to a bar where he confronts a suspicious owner named Ponytail. Tension escalates when Paul is forced to wrestle information from a reluctant Ponytail, and in a chaotic turn, Fish makes an ill-fated entrance, resulting in a deadly shootout.
Paul's interrogation methods grow increasingly desperate as he confronts Joe, a mechanic tied to Lucy's murder. After torturing him for intel, Joe spills the details of a sinister mastermind named Knox, ultimately meeting a gruesome fate himself. With the police informing Paul that Jordan has regained consciousness, he rushes to the hospital to reveal to her the harrowing truth about her mother.
However, the dark path Paul has chosen comes with a price. An ominous message from Knox threatens to expose his vigilantism unless Paul complies with a serpentine arrangement. This culminates in a bloody shootout at a nightclub, where Knox narrowly escapes a showdown with Paul. When Knox attempts to invade Paul's home, the stakes reach an explosive climax. Paul protects Jordan, who bravely calls out to him during a deadly encounter with Knox. In a moment of raw determination, Paul retrieves an assault rifle and eliminates Knox, ensuring his daughter's safety.
As the police arrive, the lines between right and wrong blur, with [Detective Raines] suspecting Paul to be the elusive "Grim Reaper." In a moment of uneasy calm, Paul drops Jordan off at the university. A chilling radio broadcast speculates about the vigilante's whereabouts, with Paul catching sight of a thief as he leaves, pointing with a finger gun, hinting that his fight for justice may not be over just yet.
