While the detectives are escorting a suspect down the courthouse steps, a sniper shoots Rollins in the shoulder. She's rushed to the hospital as Benson and Amaro frantically search a nearby rooftop, but find no suspect. It looks like the SVU squad has a cop killer on their hands.
Fin visits Rollins in the hospital to tell her that the bullet wound was through-and-through, meaning Rollins should fully recover. Unfortunately, they have no suspect in custody. The squad is running forensics on the bullet and checking security footage from the surrounding area, but they have no leads yet.
The detectives follow up possible leads, but find no suspects to pin the shooting on. When Benson receives notice of another shooting matching the same M.O., it becomes clear that the shooting was not personal. Fin and Benson head to the hospital to learn more about the second sniper victim. They quickly discover that the victim is the son of Fin's former vice lieutenant. It seems that the shooter is targeting associates of Fin.
The forensics report comes back on the gun used in Rollins' shooting. It's a very specific type of pistol that must've been shot by a trained marksman. It's also the same gun that was used in a homicide 15 years ago. Fin's vice team made a lot of enemies back in the day, so there's no telling who could be responsible. Fin and Amaro meet with Fin's old partner Luis to dig for leads, and they come out with the name of a big time drug dealer, Escobar, who tried to shoot Fin once.
Fin and Amaro head to the prison to meet with Escobar. Benson discovers that Escobar was having a relationship with his prison nurse, who has been in contact with one of Escobar's old acquaintances, Calvin Pearly Jones. Calvin is a trained marksman and the best suspect they have right now.
Fin and Benson track down Calvin at a massage parlor. Calvin assures the detectives that he isn't involved with Escobar anymore. Back in the prison visiting room, Fin and Amaro rough up Escobar in search of answers. The prison warden interrupts to inform them that Escobar's nurse has just been shot. It seems Escobar may not be calling the shots after all.
With three victims on the record, Detective Alex Eames comes in to assist with the investigation. Now that Escobar's nurse/girlfriend has been attacked, the detectives suspect that a rival gang may be to blame. Fin meets with his old partner again, who gives Fin more grief for dropping out of touch with him. He also tells Fin that he has the gun that was used in the shooting.
Back at the station, Luis confesses to shooting all three victims, but Rollins doubts that Luis was actually responsible. Instead, Rollins suspects that Luis' daughter, Gloria, may be the real shooter. Cragen discovers that Gloria was kicked out of the academy two months prior. Could Luis be confessing to protect his daughter?
Later, Gloria's car turns up with a burned body inside. Once the body is identified as a traffic officer, the squad utilizes the entire police force for a citywide manhunt. The squad tracks her to an abandoned hospital where they discover a dead security officer. During a search of the hospital, they discover a video manifesto in which Gloria confesses to the murders and details her motives. Meanwhile, Gloria heads to the suburbs to kill again.
The police find Gloria's car parked outside of her former house, now occupied by a family. Gloria is holding the family's wife and child hostage inside the house. On the phone, Gloria demands to speak to her father. Luis gets on the phone and urges Gloria to let her hostages go. Gloria blames everything on Fin and threatens to shoot the hostages unless Fin goes inside. Fin, feeling partially responsible for the disintegration of Luis' family, agrees to enter the house with Gloria.
Once inside, Fin removes his bulletproof vest and tells Gloria to shoot him instead of the hostages. He tells Gloria that he feels responsible for what happened to Luis. When Gloria is about to shoot the hostages, Fin manages to tackle and disarm her. The SWAT team rushes the house, but Fin prevents them from killing Gloria. She's taken into custody and Luis is grateful that Fin spared his daughter's life.