It's a beautiful summer day, and the detectives have the day off. Cragen and Fin catch a baseball game while Amaro and Rollins spend time in the park. At a nearby halfway house, two men finish their kitchen duties. One of the men, Lewis, shows the other how he can tolerate pain by burning his fingertips on the grill. He's clearly a demented individual.
Rollins' day in the park is interrupted when two teen girls run out of the bushes chasing after Lewis, the man from the shelter kitchen. The two girls and a witness tell Rollins that Lewis flashed his private parts to the girls in the park, so Rollins takes Lewis to the station for questioning. Unfortunately, Lewis has no identification and his fingertips have been burned off, making it impossible to prove his identity.
Rollins calls the entire squad in to assist with her investigation. It may seem like a routine indecent exposure, but Rollins has a gut feeling that there's more going on here. Cragen trusts Rollins' gut and the team splits up to interview the suspect and the victims. Meanwhile, Cragen interviews the witness, an elderly woman named Alice, in his office.
Alice tells Cragen that Lewis exposed himself to the women and said something lewd to them. Meanwhile, Benson and Amaro interview Lewis, who claims that it was all just a misunderstanding. Lewis is elusive when Benson asks about his background. Benson and Amaro get the same feeling that Rollins had before: this guy is definitely not what he appears to be.
At the request of the detectives, Barba decides to arraign Lewis to buy some time so that the detectives can investigate his past and find out who he really is. In court, Barba suggests a simple plea bargain, but Lewis refuses to plead guilty. Lewis is suspiciously "touchy" with his young, inexperienced public defender. Something is definitely wrong here. Perhaps they'll learn more when the case goes to trial.
Benson suspects that Lewis is playing hard to get so that they can't take his DNA and discover his identity. Cragen heads to the home of Alice, the witness from the park. He thanks her for her cooperation with the investigation and asks her if she'll be willing to testify in court. She dismisses the question and closes the door. Unbeknownst to Cragen, Lewis is inside the apartment, holding Alice at gunpoint.
The next day, the detectives are called to Alice's apartment when a neighbor discovers her tied to the bed, bleeding and horrifically abused. She's still alive, and she immediately tells Benson that Lewis is to blame. Over the course of 18 hours, Alice was raped, beaten, assaulted and branded with a number of household objects heated up on the stove. Cragen is appalled by the torture and feels incredibly guilty. Amaro assures him that Alice is a tough woman, and she'll make it through this.
S.W.A.T. teams and police officers swarm on the halfway house that Lewis is staying in, but the owner tells him that Lewis disappeared two days ago. Fin and Rollins charge into Lewis' old room and find Lewis' roommate, who says that their suspect hasn't been around lately. The detectives discover the Lewis likes a particular alcoholic energy drink that's only sold in one shop. Fin and Rollins stake out the shop and arrest Lewis later that night.
Back at the station, Lewis denies everything. Lewis tries to egg Benson on by telling her the graphic details of his abuse of Alice. Unfortunately, his entire confession is hypothetical, so it can't be used against him in court. By now it's clear that the detectives are dealing with a deeply disturbed but clever psychopath. Lewis' lawyer arrives and the questioning stops immediately.
Barba tells Benson that the confession won't hold because it was couched in a hypothetical statement. Nonetheless, Lewis' DNA is all over Alice and her apartment. Barba says they'll need Alice to either testify or identify Lewis in a line-up as soon as she's released from the hospital. Meanwhile, Rollins continues to search for Lewis' background information, but it's difficult with only a name to go by.
The next day, Alice stops by the station. Cragen apologizes deeply for what happened to Alice. Amaro informs Cragen that Lewis tried to choke himself during transport, so he conveniently won't be available for a line-up. The judge orders Lewis to undergo a psych evaluation before he can be tried. Luckily, the detectives get a break: Rollins managed to track down Lewis' true identity and criminal history.
15 years prior, Lewis abducted and raped his ex-girlfriend's mother, then got off on a technicality. Later, he kidnapped, raped and tortured two roommates and got off on another technicality. If there's a break, Lewis seems to catch it. In a later case, Lewis began sleeping with his defense attorney. Months later, she turned up dead and Lewis got off on yet another technicality. Cragen assures his team that Lewis will not get off again.
Cragen and Benson return to Alice's apartment to inform her that she'll need to testify against Lewis. When they arrive, they find that Alice has suffered a heart attack. Back at the station, Barba explains to a frustrated Benson and Rollins that it will be difficult to convict Lewis without a solid witness. During a prison visit, Benson plants a seed, informing Lewis' new attorney/girlfriend that he murdered his last defense attorney/girlfriend.
When the case goes to trial, Lewis' attorney attempts to systematically convince the jury that the SVU detectives have a vendetta against Lewis. She also discredits the deceased victim, Alice, by pointing out her vision problems. The final nail in the coffin, though, is when Lewis' attorney discovers that the DNA samples were tainted in the laboratory, thereby negating any DNA evidence in the case and forcing a mistrial. Once again, Lewis gets off on a technicality.
Back at the station, the detectives receive word that Lewis' attorney paid his bail, so he's a free man. Rollins and Fin lament the defeat by heading to a bar. Amaro heads home to be with his family, and Cragen tells Benson to take two days off to relax. Benson heads home to her apartment to find Lewis waiting for her. He holds a gun to her head and drags her to the bedroom.