In the nighttime sky over San Francisco, a police helicopter responds to a report of a body in Presidio Park. On the ground, two detectives kneel beside a dead man in his mid-30s, badly beaten and with a single gunshot wound to the head. One of them asks, "Well?" The other replies, "We need to call the FBI. It's starting again."
Elsewhere in the city, a man and his teenaged daughter walk up the street while discussing their family's domestic issues. When they stop on the sidewalk for a moment, a man who's been following them orders them at gunpoint to "come quiet, or you both die."
Hotchner meets with his BAU colleague and friend, SSA Sam Cooper, about the Presidio Park case. Two years earlier, four men were found dead in the park in as many days. Each of them also had suffered massive blunt-force trauma injuries, defensive wounds, and a single gunshot wound to the head. Exactly one year later, the pattern repeated itself with four more men. Now, another year later, the pattern is starting for a third time.
Cooper has observed in the first and second years, a father and his teenaged brunette daughter were found murdered in San Francisco on the day after the fourth man was found. Convinced that the killings are related, Cooper wants in on the current case. With only three days to find this unsub, Cooper's team would handle the father/daughter angle while Hotchner's team concentrates on the park victims. Hotchner immediately understands: Cooper had already approached the Director, who denied his request to investigate. Cooper is certain another father and daughter are missing right now, and no one is looking for them.
The father and daughter are seated on the floor in an old building, and both chained to a pillar. The kidnapper says if the father gives him the girl, he'll spare them both. The father retorts, "Go to hell." The kidnapper replies, "If that's your answer…" and walks away.
Mother Teresa: "I have found the paradox, that if you love till it hurts, there can be no more hurt. Only more love."
On the BAU jet, the team theorizes that the unsub is targeting vulnerable people who wouldn't be missed as part of a larger plan that he carries out during the same few days each year. The dates have no historical significance, so they must be of personal importance to him. Hotchner assigns Reid and JJ the police department, Rossi and Prentiss to the crime scene, and Morgan and himself to the coroner's office. Except for Rossi, the others are concerned about Hotchner's risking his own neck to involve Cooper in the case. Rossi has known Cooper for 20 years and has faith in the latter's instincts.
Beginning of Day One. Cooper and his team -- SSA (pending) Jonathan "Prophet" Sims, SSA Mick Rawson, and SSA Gina LaSalle -- set up their operation in San Francisco. They begin their search by checking school absences for brunette girls ages 13 to 18, then checking those girls' fathers to see who also hasn't shown up for work.
At Presidio Park, a SFPD detective tells Rossi and Prentiss that the male victims all came from the same few blocks in the city's Tenderloin district. At the coroner's office, Hotchner and Morgan observe the body of the newest victim. There are bruises on his knuckles, and gunpowder residue on his skull. He was taken without anyone noticing, then fought for his life only to let the unsub shoot him execution-style. What on earth is the unsub doing with these homeless men?
The father, unchained, stands in the center of a rectangular pit. Another man is handcuffed to a ladder at one side of the pit. Standing above with a pistol in one hand, the unsub tosses the father a key and orders him to release the other man. The father does, and the other man immediately slugs him.
The unsub orders the father to get up and says, "You win, you live. You lose, I kill your daughter and I kill you. Understand?" Eventually the father beats his opponent unconscious. After repeatedly asking, "Can you stand?" and getting no answer, the unsub fires his pistol into the pit.
Sims learns that 14-year-old Jane McBride missed school both that day and the previous day. Her father, Ben McBride, also hasn't been seen at his contracting company for two days.
Beginning of Day Two. Hotchner and Cooper visit the McBride home. Mrs. McBride quickly brings them inside, saying, "You just got my family murdered." She shows them a DVD of the first park victim, bound and kneeling, being killed execution-style. A man called and warned her not to contact the police, then sent the DVD to back up his threat.
With Cooper's theory confirmed, Hotchner suggests that his own team take it from there. Cooper insists on staying. Long ago he and Hotchner worked on a case involving five child murders, and identified a suspect but believed he wasn't responsible for all the murders. They weren't allowed to pursue their theory of a second killer, which was confirmed when said killer was caught dumping another child's body. Cooper refuses to ignore his gut feeling again.
A second body is found in Presidio Park. Prentiss and Rawson go to the scene, while Morgan and LaSalle stay with Mrs. McBride to protect her.
Rawson observes that the first victim had scratch marks on his chest, and the second has skin under his fingernails. Prentiss realizes that they fought each other, not the unsub. The unsub kidnapped several homeless men, forced two of them to fight, and killed the loser. Then he took the father and daughter, using the first killing to keep the wife from contacting the police. Welts on the second body look like those made by rubber bullets, the kind used to control rioters or prison inmates. Rawson theorizes that the unsub has served prison time. He and Prentiss call their respective teams.
Rossi and Sims visit San Quentin Prison, where Sims reveals that he himself served six years there. While Rossi and Sims describe the unsub to current inmate and Sims' friend Nelson G, Hotchner and Reid give the profile to the San Francisco police. Morgan and LaSalle also tell Mrs. McBride about the unsub, in hopes of determining why he targeted Jane.
Hotchner and Prentiss meet up with Cooper and Prentiss. Cooper says they need profilers as well as police patrolling the Tenderloin district. The unsub may seek another victim to fight Ben McBride. That evening Rawson, a crack sniper, takes up a rooftop position while Prentiss has eyes on the ground.
Ben McBride is being forced to fight again because he still refuses to give Jane to the unsub. He knocks his opponent unconscious, and then defiantly shouts, "You won't break me!" This time the unsub threatens to kill Jane if Ben doesn't finish the loser off.
Beginning of Day Three. Both teams gather at Cooper's base, to analyze the prison inmate data Garcia compiled based on the profile. Sims receives a phone call, and he and Rossi leave for another visit to San Quentin. Nelson G tells them about a previous inmate who was supposedly "all kinds of crazy", and "went all commando" after his daughter died. He began boxing and working out, and challenging everyone in the yard to a fight to the death. Eventually he began challenging the prison guards too, and served the rest of his time in solitary confinement.
At the McBride's house, LaSalle sees clear signs in Jane's bedroom that the girl is emotionally distant from her parents. Yet she has a journal, going back only nine months, on her desk where anyone could read it. Mrs. McBride explains that the family went to a counselor who suggested that Jane keep a journal. The counselor's office is in the Tenderloin district.
The therapy center the McBrides visited also performs evaluations for social services. Sims calls Cooper with a name: John Vincent Bell. Bell was divorced, and his ex-wife died some time later. Because of mental health issues, he was declared incompetent to have custody of their daughter Mandy. When social service workers came to take the girl, Bell beat one of them to death and was sentenced to seven years for manslaughter. During that time, Mandy was injured in a car crash and died three days later.
Bell performs his annual ritual on the anniversary of Mandy's injury and subsequent death. He kidnaps fathers and daughters who are in difficult family situations. Then he forces the fathers to fight to the death, to prove that he himself had done what any father would do. Garcia finds a local address for Bell, a gymnasium belonging to his family which hasn't been operational in years. The pit where his victims fought was the empty swimming pool.
Ben McBride still won't break, but Jane finally does. To stop Bell from forcing her father to fight again, Jane agrees to go with him. They depart, leaving Ben still chained to the pillar.
The police and the FBI teams raid the gym minutes later and rescue Ben McBride. Rawson heads for a rooftop position, while Cooper takes a police helicopter to direct the search from the air. Cooper spots Bell and Jane on the street, and the two run into the nearest building. Morgan, Prentiss and LaSalle follow and corner them on the roof. Bell releases Jane and goes over the wall.
Prentiss, her weapon holstered, runs to the wall and looks over the side. To her surprise Bell lies on a ledge just feet below, unharmed. He sits up and aims his gun at her, but before he can fire he is shot by Rawson from a rooftop across the street. Ben McBride will recover from his injuries, and his family is reunited.
Later, both teams later celebrate their success. Cooper says to Hotchner, "Thanks for putting yourself on the line for me." Hotchner replies, "Any time. Thanks for being right."