The story is set during a boxing match at the Hopi A.C. between Jack Maloney, an Irish-American fighter, and Tony Azerello, an experienced Italian boxer, witnessed by the narrator and police inspector Hanlon. The atmosphere is charged with tension, partly due to the presence of Malissa di Gigisetti, Azerello's passionate and fiery Sicilian girlfriend, who vocally supports him and curses Maloney.

Maloney, despite being outclassed and heavily battered throughout the fight, manages to land a devastating punch on Azerello in the tenth round, seemingly knocking him into the ropes. At that exact moment, the lights go out. When they come back on, Azerello is found fatally injured, having died from a blow to the head that occurred when he supposedly fell against the thinly padded edge of the ring.

Malissa's grief at Azerello's death is profound, and she vows revenge against Maloney, who is later acquitted of any wrongdoing due to the death being declared an accident. However, Maloney is subsequently attacked and severely wounded by an unknown assailant, believed to be acting on behalf of Malissa's father, a man with Mafia ties.

The narrative takes a mysterious turn with the introduction of William J. Karney, the new caretaker at the Hopi Athletic Club, who reports an eerie encounter with the ghost of Tony Azerello. The ghost leads Karney to discover a blood-stained seat in the arena, marking the spot where Azerello's true killer, Luigi Savonari, sat during the fight. Savonari, driven by jealousy and rage over Malissa's affection for Azerello, confesses on his deathbed to murdering Azerello in the darkness when the lights went out, using a slung shot to deliver the fatal blow.