After retired professional hitman 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, which John refuses to sell. That evening the gangsters break into John's 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, deduces that the car was stolen from John. He punches Iosef and throws him out. Aurelio was visited by John, who identifies Iosef as the son of Viggo Tarasov, the head of the Russian crime syndicate in New York City. Aurelio relays Iosef's activities to Viggo, who beats and berates Iosef before explaining to him who John Wick is: a famed assassin, formerly in Viggo's employ, nicknamed "Baba Yaga". When John wanted to retire and marry Helen, Viggo gave him an "impossible task," implied to involve multiple high level assassinations in a short period of time. John succeeded, and his efforts were key in establishing the Tarasov syndicate. After warning Iosef of his impending doom, Viggo tries to talk John out of seeking retribution, but John refuses to even talk. Viggo sends a team of hitmen to John's house, but John kills all of them and enlists an underworld cleaning service to dispose of the bodies and evidence.
Unsurprised, Viggo places a $2 million bounty on John's head and personally offers the contract to John's mentor, Marcus, who accepts. John seeks assistance from the New York 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 this rule to kill John. Winston, the Continental's manager, informs John that Viggo has Iosef under guard at his nightclub, the Red Circle. John enters the Red Circle and kills a horde of thugs to reach Iosef, who narrowly escapes after Viggo's lieutenant Kirill manages to incapacitate John. John retreats to the Continental to have his injuries treated. Ms. Perkins, an assassin and former acquaintance, sneaks into John's room to kill him. Marcus alerts John, allowing him to subdue Perkins, who is forced to reveal the location of Viggo's front. He knocks her unconscious and leaves her with Harry, a fellow assassin, to await punishment, but she frees herself and kills Harry. John travels to a church in Little Russia which serves as Viggo's front and destroys his cache of money and blackmail material. When Viggo and his henchmen arrive, John ambushes them, but he is subdued and captured. Viggo taunts John for thinking he would be able to leave his old life behind. Before John can be killed, Marcus intervenes again, allowing John to free himself, kill Kirill, and accost Viggo, who reveals Iosef's location. John then travels to Iosef's safe house and kills him and his bodyguards.
Perkins learns that John and Marcus have been in contact and informs 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 summoned to a meeting with Winston, who orders 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 New York Harbor, where he kills Viggo's remaining henchmen before fighting Viggo on the dock. Viggo pulls out a knife, and John allows himself to be stabbed, then disarms and fatally wounds Viggo. John breaks into an animal clinic to treat his wounds and releases a pit bull puppy scheduled to be euthanized. John and the dog walk home along the boardwalk where he had his final date with Helen.
Credits: Warner Bros. Entertainment, Lionsgate, eOne UGC, LeakID, Studiocanal, M2 Pictures S.P.A., CPRAgency for Belga Films, CoPeerRight Agency - Italy