Less than an hour after the events of the second film, former hitman said yes York Public Library and retrieves two concealed items – a “marker” medallion and a crucifix. Then he is injured following a fight with a giant assassin named Ernest. Wick leaves to get medical treatment, but his excommunicado begins before the doctor can finish. Wick patches the injury himself and leaves but is found by a gang and after a fight in an antique dealership escapes onto the streets.
John meets with Director, the head of the Ruska Roma, with the crucifix and requests her help in getting safe passage to Casablanca. The Director reluctantly helps, as John is a former protégé and is from Belarus, knowing that this act will violate her peace treaty with the High Table. An Adjudicator of the High Table meets with Winston, the manager of the New York Continental, and the Bowery King, the leader of a network of vagrants. The Adjudicator punishes both for helping John, giving them seven days to resign their positions, and hires Zero, a Japanese ninja. Zero and his students find the Director, slaughtering her guards and stabbing her hands as punishment for helping John.
In Casablanca, John meets Sofia, a former friend and the manager of the Moroccan Continental. He asks her to honor a debt she owes him for aiding her daughter by directing him to the Elder, the only person above the High Table. Sofia takes John to Berrada, her former boss, who tells John he may find the Elder by wandering through the desert until he cannot walk any longer. In exchange, Berrada asks for one of Sofia’s dogs; when Sofia refuses, he shoots the dog, which is saved by a bulletproof vest. In retaliation, Sofia tries to kill Berrada but at John’s warning, she only wounds him. Sofia and John fight their way out of the kasbah and drive into the desert, where she leaves him.
The Adjudicator and Zero confront the Bowery King, who refuses to abdicate his position. Zero’s students slaughter almost all of his henchmen. As penance for helping John, Zero cuts the Bowery King seven times with a wakizashi.
Collapsing in the desert, John is brought to the Elder. John says that he is desperate to live to “earn” the memory of the love he once had with his wife. The Elder agrees to forgive John on condition that he assassinate Winston and continue to work for the High Table until his death. To show his commitment, John severs his ring finger and offers his wedding ring to the Elder. John returns to New York City and is attacked by Zero and his students, before reaching the protection of the Continental. John meets with Winston, who encourages John not to die as an killer but as a man who loved, and was loved by, his wife.
The Adjudicator arrives, but Winston refuses to give up his office and John refuses to kill Winston, leading the Adjudicator to “deconsecrate” the Continental, revoking its neutral ground status. The Adjudicator notifies Zero and sends heavily armed and armored enforcers to kill John and Winston. Winston furnishes John with weapons, and alongside Charon and other hotel staff, John defends the Continental. After killing the enforcers, John is ambushed by Zero and his students, and kills all but two students and fatally wounds Zero.
The Adjudicator agrees to a parley with Winston, who explains his rebellion as a “show of strength” and offers fealty to the High Table. After John arrives, the Adjudicator questions what should be done with him. Winston shoots John repeatedly, and he falls from the Continental’s roof. The Continental is “reconsecrated”, but the Adjudicator informs Winston that John’s body has disappeared, and that he remains a threat to them both. A seriously injured John and his dog are delivered to a now heavily scarred Bowery King. He tells John that he is really pissed off at the High Table; asking John if he is too. The film ends with John saying, “Yeah”.