After John Wick loses his wife Helen to a terminal illness, he receives a beagle puppy named Daisy from her to help him cope with his grief. Despite John’s stoic demeanor, he bonds with the puppy and they spend their day driving around in his vintage 1969 Ford Mustang Mach 1. At a gas station, he encounters a trio of Russian gangsters whose leader Iosef insists on buying his car, but John repeatedly states that it is not for sale. Frustrated, the mobsters follow John to his home, knock him unconscious, steal his car, and kill Daisy.
Iosef takes the Mustang to a chop shop to have the VIN changed. Aurelio, the shop’s owner, recognizes the car and, upon learning that Iosef stole it from John, punches Iosef before kicking him out of his shop. John visits Aurelio, who identifies Iosef as the son of Viggo Tarasov, the head of the Russian crime syndicate in New York City. Viggo, informed by Aurelio of Iosef’s activities, beats and berates Iosef before explaining to him who John Wick is: A famed assassin formerly in Viggo’s employ, nicknamed “Baba Yaga” (translated in the film as Russian for ‘”Boogeyman”‘). Previously, when John wanted to retire and marry Helen, Viggo gave him an “impossible task”, implied to involve multiple assassinations in a short period of time. John succeeded, and his efforts were key in establishing the Tarasov syndicate.
Viggo tries to talk John out of seeking retribution, but John refuses. Viggo then sends a twelve-man hit squad to John’s house, but John kills them all and has the bodies professionally removed. An unsurprised Viggo places a $2 million bounty on John’s head and personally offers the contract to John’s mentor, Marcus, who accepts the offer. John seeks refuge at the Continental Hotel, which caters exclusively to the criminal underworld and permits no assassinations on its premises. Viggo doubles the bounty for those willing to break the rules to kill John at the Continental. Winston, the Continental’s owner, tells John that Viggo has Iosef under guard at his nightclub, the Red Circle. John enters the Red Circle and makes his way to Iosef, but Viggo’s henchman Kirill waylays John, allowing Iosef to escape.
John retreats to the Continental to patch up his injuries. Ms. Perkins, an assassin and former acquaintance, sneaks into John’s room to kill him, but Marcus alerts John, allowing him to subdue Perkins. John forces Perkins to reveal the location of Viggo’s front, knocks her unconscious, and leaves her with Harry, a fellow assassin, to await punishment. However, Perkins frees herself and kills Harry. John travels to the Little Russia church, which serves as Viggo’s front, and destroys Viggo’s cache of money and blackmail material. When Viggo and his team arrive, John ambushes them, but is subdued and captured. Viggo taunts John for thinking that he could leave his old life behind. Marcus intervenes again, allowing John to free himself and to kill Kirill before accosting Viggo, who (implied to be tired of his son’s behavior) reveals Iosef’s location. John then travels to the safe house, killing Iosef and his bodyguards.
Perkins learns that John and Marcus have been in contact and tells Viggo, who has Marcus beaten and tortured before executing him in his home. Viggo calls John to report this, planning to have Perkins ambush him. While waiting for John, Perkins is called to a meeting with Winston, who has her executed for killing Harry on Continental grounds. Winston calls John to inform him that Viggo is planning to escape by helicopter. John races to the harbor helipad, where he kills Viggo’s remaining henchmen before engaging Viggo in a battle on the dock. Viggo pulls out a knife, and John allows himself to be stabbed, surprising Viggo. John then disarms Viggo and fatally wounds him. John breaks into a waterfront animal clinic to treat his wound and releases a pit bull puppy scheduled to be euthanized. John and the dog walk home along the boardwalk, where he had his last date with Helen.