Parker Hubbard comes home to celebrate an anniversary with his girlfriend, Lily Reiser, but Lily is nowhere to be found. The bedroom is a mess and there is broken glass and blood everywhere. Stabler and Benson investigate the scene and the bloody handprint on the windowsill matches Lily's prints. Parker tells the detectives the "perv" downstairs neighbor must have done it. Stabler and Benson go to question the neighbor, Callum Donovan, but Donovan already knows Stabler: Stabler put him in jail for 19 years the last time they saw each other.
Back in 1989, Stabler accidentally caught Donovan robbing a bank when Donovan ran into Stabler trying to make a get away. Donovan, now a suspect in Lily's kidnapping, is taken down to the precinct for questioning. Cragen orders Stabler to talk to Donovan to try and use the past to get information about the missing girl. Donovan denies having anything to do with Lily's disappearance. Stabler tries to get him to admit to fantasizing about Lily. Calmly, Donovan denies everything. He claims he goes up to the roof to get fresh air. Benson interviews Parker who talks about how amazing Lily is while Donovan tells Stabler how Lily is a nut for yelling about his smoking. Donovan won't change his story. Emotionally, he talks about how he doesn't want any excuse for the cops to put him back in jail. It's apparent that the 20 years Donovan spent in prison has taken a toll on him. Donovan's lawyer, Petra Gilmartin, shows up and stops the interrogation.
Paxton and Stabler start to butt heads again when Paxton wants more proof to arrest Donovan. Stabler is convinced Donovan is the guy, but Paxton thinks it's all hearsay. Although Cragen is on Stabler's side, Paxton has the last word. Stabler thinks if they let Donovan go it will give him time to clean up the kidnapping mess. Petra, Donovan's lawyer, forces the detectives to let him go because of lack of evidence.
Stabler and Benson follow Donovan's every move. The detectives go down to where Donovan works. Donovan's boss gives Benson and Stabler Donovan's time card from the day of Lily's disappearance. The foreman stands up for Donovan and says how after work the boys went down to a bar and got a drink. The foreman tells the detectives that sometimes people change. Benson doesn't think so. Stabler decides to have Munch and Fin come and stakeout Donovan's workplace while Stabler and Benson go down to the bar where Donovan went after work.
At the bar, Stabler and Benson interview the bartender, Betty. Betty obviously cares for Donovan. Betty talks about how she and Donovan were friends before he got sent away the first time. Betty tells the detectives that she and Donovan were trying to get involved with each other. The night of Lily's kidnapping, Betty and Donovan were trying to be intimate, but according to Betty, Donovan couldn't "cut the mustard" because he was drinking. Betty says that Donovan left pissed off, breaking a lamp and calling her a whore.
Benson gets a phone call that Lily's body has been found right off Staten Island. When Stabler and Benson get to the scene they have a pleasant surprise waiting for them: Lily is still alive. Parker rushes into the hospital to see how Lily is doing and immediately updates his "Twitter" account, "Where's Lily" to let her "fans" know that Lily is alive. Benson and Stabler go into Lily's hospital room to ask her questions about the kidnapping. Lily is distraught and emotional and tells Benson that she came home from school and she was attacked. She isn't quite sure who the attacker was, but it "might be the creep from downstairs." For Benson, this isn't enough to arrest Donovan.
The detectives are confused and try to figure out where Donovan could have been keeping Lily. Cragen says that Munch and Fin have been watching Donovan all day, so there is no way he could have dumped her body. Benson knows Lily couldn't have been in the river all night because the current would have dragged her out to sea. Stabler thinks Donovan wanted to have more fun with Lily. Benson brings up the fact that Lily said she was kept somewhere cold, maybe Donovan kept her in a refrigerator at work.
The detectives go to the docks to check to see if Donovan stored Lily in a refrigerator there. But forensics can't find any of Lily's prints. Donovan, impatient and depressed, tells Stabler to go ahead and put the cuffs on already. Stabler's cocky attitude about Donovan's guilt is apparent to everyone. Fin shows Stabler Lily's Twitter. Fin says some people are saying that they saw Lily while she was supposed to have been kidnapped. It appears as though at midnight, Lily was seen at copy center arguing with a man outside. The only problem is that Donovan was in the interrogation room at midnight.
Stabler interviews Tracy, who is a clerk at the Copyquick and a Lily Twitter follower. Stabler shows her a picture of Donovan and Tracy does not identify Donovan as the man with whom Lily was fighting. She states that the guy Lily was arguing with was Asian. Stabler wants to make sure that Tracy isn't misidentifying Lily and to his surprise, Tracy has a receipt with Lily's information. Lily, on the supposed night of her kidnapping, came into Copyquick and wrote a bunch of emails. Looks like Stabler has a new suspect to catch.
Stabler and Benson confront Lily at the hospital. Stabler asks her about Billy Chang, a meth dealer. Lily denies Billy having anything to do with the kidnapping. Stabler shows Lily the emails she wrote to Billy asking for more meth. Stabler confronts Lily and tells her that the detectives know she lied. Lily admits to her drug problem. She trashed her own apartment then banged her head on the mirror when she couldn't find a hidden stash. She didn't want Parker to find out about it and escaped out the window. Once Lily saw she had a Twitter fan base, she decided to fake her own kidnapping. Although Lily doesn't think there was any harm done, Benson puts the cuffs on the faux kidnapped victim.
Stabler knows he has to apologize to Donovan. He finds him on the rooftop of the apartment building, and before Stabler can speak, Donovan, in a state of panic, pushes Stabler off the roof. Stabler is put in the hospital and luckily survives the fall. At the hospital, Paxton, Cragen, and Benson tell Stabler that they have everyone looking for Donovan. Fin comes in and says that he hasn't found any sign of Donovan, but there is one lead. Fin and Benson go to check it out.
Benson and Fin pay a visit to Veronique St. Johns. Veronique hosts a private group home for seniors. Mrs. Donovan, Donovan's mother who suffers from Alzheimer's, is housed there. Benson and Fin find Donovan in Mrs. Donovan's room. Donovan goes quietly until the detectives bring him outside. Then he tries to run and wants Benson to shoot. Benson tells Donovan that Lily faked her own kidnapping and that Stabler went to tell him about it and apologize. Donovan is stunned and defeated.
At the precinct Stabler goes into the interrogation room to talk to Donovan, despite Paxton's warning. Stabler forces Donovan out of his chair. Cragen breaks it up and Paxton yells at Stabler. Paxton and Stabler get into it. Stabler finally stands up to Paxton. He tells Paxton that he doesn't work for her. Paxton tries to break Stabler down by calling him "the victim," but Stabler tells her that she is weak and like any other perp that walks in the door. Paxton, flustered and emotional, slaps Stabler in the face. Stabler laughs this off and Paxton is left almost in tears.
At Donovan's arraignment, he pleads not guilty. His lawyer, Petra, will pursue a psychiatric defense. Paxton is appalled and says that Donovan has lived a well-maintained life up until now with no history of mental illness. Petra explains that during Donovan's time in jail he spent the majority of the sentence in solitary confinement. The judge allows the defense and Donovan pleads to not put him back in solitary. Stabler looks on unmercifully as Donovan gives a speech about the torture that occurrs in the prison system.
At the precinct, Munch has a few opinions about the prison system. Stabler is surprised that Munch is taking Donovan's side. Benson opposes Donovan's case when she talks about her own undercover time in prison. Benson says that she would have loved some privacy away from the inmates. Munch talks about a study of how solitary confinement causes psychosis. Munch says the mind can survive prison but, "We're not wired to be alone."
Donovan takes the stand and talks about solitary confinement. In prison, he didn't want to become part of the Aryan nation and he was thrown in the hole for protection. Donovan admits he spent 15 years in confinement. His testimony is haunting. He describes the lack of sleep, the voices in his head, and the shadows on the wall turning into people. Stabler suddenly seems interested and touched by what Donovan is saying. Donovan tells Stabler that he cannot imagine what it's like.
Stabler, inspired by Donovan's testimony, calls in a favor at the prison. Stabler asks to be put in solitary confinement for three days. He enters the cell and looks around. There is no window and he is surrounded by concrete. Stabler spends his time doing push-ups, crunches, pacing. When a guard gives Stabler a tray of food, Stabler asks, "What time is it?" but no one answers. By the end of the third day, Stabler has cracked.
After spending three days in the hole, Stabler tells Paxton that he wants to drop the charges. Paxton thinks Stabler is being a wimp, and will not plea bargain with Donovan. Paxton thinks this will give any perp a free chance to kill a cop. Stabler tells Paxton he will report her for slapping him in the face. Paxton calls Stabler's bluff and says, "You may have lost your balls in lockup, but I've still got mine."
In court, Donovan is found guilty and taken away. There are cheers from the crowd, but none from Stabler. Donovan pleads for the judge to put him out of his own misery. As the guards take Donovan away he keeps saying, "Please, please." Paxton meets Stabler at the bar and wants to buy him a drink, but Stabler refuses. Stabler angrily walks out of the bar and leaves a guilt-stricken Paxton alone.
Stabler visits Donovan at the prison. The guard tells Stabler that he is drugged up because he wouldn't stop slamming his head into the wall. The guard takes Donovan away and says that the warden ordered him be put in general population and not in the hole. Stabler finds out that Paxton pushed the warden to do it and wouldn't take "no" for an answer.