Stabler and Benson investigate a murder scene, where a young woman has been found in Central Park stabbed to death and her jewelry still intact, including her wedding ring. A license reveals she was from Kansas. Further investigation reveals the word "Guilty" written on her forehead in blood, as well as a pacifier in her hand. Shortly after, police find her baby in a stroller with word "Innocent" written on his forehead in blood.
Fin and Munch find out that Peter Harrison was performing community service in the area that morning and had to leave early for having a cut hand. The detectives visit Peter at his apartment, to find he's paranoid and maintains the NYPD is always watching him. He agrees to follow the detectives to the SVU if that means he will stop being followed. Stabler takes advantage of having Peter in custody in the interrogation room. His lawyer, Julie Zimmer, shows up and tells him he has the right to leave.
After Julie is able to prove that the evidence collected by Dale in Peter's apartment was contaminated by evidence found at the crime scene, Judge Donnelly throws out the murder charges against Peter. Dale swears to Stabler he did everything right when collecting evidence, but Stabler is tired of hearing his excuses. Meanwhile, as Peter walks away a free man, Fin and Munch track his every move.
After Fin and Munch lose Peter in Coney Island, another murder takes place and it fits Peter's M.O. A thumbprint found on scene proves to be Peter's. Using Peter's computer at home, detectives also discover he has been making updates on a crime conspiracy blog, where he bragged about beating the system. Once comment to Peter's post urges Peter to contact them if he needs anything. Munch recognizes the screen name.
Munch meets with his old friend Gwen at her favorite coffee shop, where he knows he can always find her. He uses his charm on Gwen, in hopes she'll tell him where Peter is hiding out. She tells him of a warehouse where Peter rents the basement as a safe room, and Munch heads out to find him. But not before she asks him for another chance to be with him. Munch rejects her advances and later reveals to Fin that Gwen is his ex-wife.
Peter sets a trap for Stabler and Fin before escaping his "safe room." Stabler and Benson turn to Julie for help on where to find him. She insists her hands are tied and she's just as worried about her client as they are, since she's been a mother figure to him since his parents died in a plane crash when he was 17, and she represented him in his civil suit. With Julie's help, Stabler and Benson discover Peter went to the New York College for Fine Arts, where he still turned in paintings, even though he was no longer a student. One look at his artwork reveals the dark world that Peter has been living in.
After Stabler and Benson receive a phone call from Julie with only the sounds of Peter screaming at his lawyer on the other end, they react quickly. At Julie's office, they find Peter rambling incoherently and then he lunges at Stabler. Stabler immediately arrests him as Benson checks in on Julie, who feels guilty for alerting them of Peter's visit in the first place. As Julie leaves, her car fills with poisonous gas and she is trapped. Benson and Stabler cannot reach her in time, as Peter continues ranting from the back of their squad car.
The detectives are quick to realize that Peter has a hit list of all the people he feels have done him wrong. They alert Judge Donnelly to Peter's recent actions. She assures them she is fine and not scared. Shortly after, she sits on a syringe and passes out. Donnelly barely makes it to the hospital in time and Benson and Stabler are relieved to find out she has survived. Just then, Stabler receives a call to return to the lab, as Benson wants to stay by Donnelly's side.
As Stabler rushes to the lab, he finds O'Halloran dead on the floor after being stabbed. On O'Halloran's computer screen is a DNA match pointing to Dale. Just then, Stabler is blindsided and hit in the head with a blunt object. The assailant then takes Stabler's gun and phone and ties him up in the lab. Stabler awakes to find Dale staring at him. Dale confesses to trying to kill Donnelly and to murdering O'Halloran. He accuses Stabler of always being mean to him and then stabs him in the chest as punishment.
Dale also confesses to the murder of Julia as well as the one in Coney Island, while making it look like Peter did it this whole time. Stabler tells Dale that it would be impossible for him to kill everybody who has ever hurt his feelings and he will leave evidence behind to tie him to his crimes. As Dale continues to become more and more unglued, he slashes more and more at Stabler's chest.
Benson shows up at the lab and finds Stabler bloodied and tied to a chair. Before she can react, Dale pulls a gun on her and tells her to not move. She begins to compliment Dale for his work at the lab, confusing him. She tells him that he solved Peter's crimes and it's obvious he wasn't capable of hurting Stabler or O'Halloran. Benson promises Dale she'll tell Cragen that he's a hero. She tells Dale that she understands his hatred for Stabler and begins screaming at Stabler, as Dale watches.
Dale keeps telling Benson that she is confusing him by yelling at Stabler and begs her to stop. She orders Dale to shoot Stabler to end their misery at having him around. She tells Dale that if he kills Stabler, she will ask Cragen personally if Dale can be her new partner in the SVU.
Dale begins to believe Benson's promise and agrees that all he has to do is murder Stabler first. Before he can pull the trigger, Benson leans in and tells Dale that before they shoot Stabler, she wants him to watch Dale and her kiss.
As Benson kisses Dale, Stabler is able to kick him in the groin and Benson hits him, knocking him out cold. She quickly unties Stabler and he wants to know how Benson knew he was in trouble. She says when she called earlier and Dale answered he told Benson that Stabler was out getting sushi and she knew he doesn't handle raw fish. Benson and Stabler take a moment to survey the scene.