Fin and Warner are called out to investigate the discovery of a dead man, a biker, tied to a tree. The man (Clyde) had his male parts cut off, and Warner notes to Stabler that the man was tasered. Fin checks the victim's pockets and discovers one of Benson's business cards inside. Meanwhile, Benson is out sick with the flu. Stabler goes to see her about the victim, but she doesn't remember ever meeting the man, and neither does Stabler. Stabler informs Benson that he's going to take care of the case.
Fin and Munch visit the headquarters of the Death Knights, Clyde's motorcycle club. The detectives try to talk to the bikers but the club doesn't want the cops involved. When a club member shows up without the right license to operate a bike, however, the detectives force him to cooperate. They bring the biker to the precinct and make him watch survellience footage of a gang rape of a girl (Starla) which the biker participated in. The biker denies that it was rape, saying that she consented to it. The night that Clyde was freed from Attica prison, Starla was given to him as a gift from his club. Starla eventually became Clyde's old lady. Cragen says that Starla's story better match, else the biker will be arrested for rape.
Stabler drops by Starla's home but she isn't there. Right before he leaves, however, he spots her, carrying a briefcase and dressed in a business suit. She panics at the sight of the detective and tries to run, but her suitcase flies open, and a lot of government documents tumble out. Starla claims that she didn't murder Clyde, and that the footage with her and the Death Knights wasn't gang rape. Starla has a job at the city clerk's office, but she's been pilfering blank birth certificates. She willingly admits that she wants to become a part of the Death Knights and has no shame for what she's done. She claims to not know Benson either.
Cragen discovers that a 911 call was placed concerning Clyde's bike. A dark haired woman in a black Mustang was spotted hitting the motorcycle, but the caller only remembered part of the license plate. When the numbers are run, however, Benson's name pops up as a possible owner of the vehicle. Cragen goes with Benson to examine her car. She says that she's been home sick and hasn't driven her car in almost a moth. However, the damage to the car (a broken headlight and a large dent) tell a different story.
The detectives all believe that Benson didn't cause the accident, and Fin says he'll try to find the person who placed the 911 call. To stave off any suspicion, Benson asks Warner to take a swab of her DNA. Fin and Munch do find the person who made the call. Khalil has a thick accent which doesn't match the voice of the caller on the tape. He says that he let someone borrow his cell phone to call 911 about a car accident. Khalil offers the detectives a description of the man, but it's too vague to be of much use. Meanwhile, the attempt to get survellience footage from Benson's garage hits a snag because the garage cycles through their tapes every 24 hours and that window has already passed. No one will be able to tell who took Benson's car. Benson is at the precinct, searching through her old case files to try and figure out her connection to the current case. Cragen tells her to go home and get some rest, and that Stabler will search through their cases.
As he tracks down the Death Knights, Stabler informs Kathy on his cell that he's working late. But then he spots a biker pouring beer all over his car. It turns out the biker is an undercover cop, Russell, who has infiltrated the gang. Russell explains that his partner is working survelliance in a nearby building and that Stabler should check things out there. Russell's partner, Detective Lewis, has been tracking the Death Knights for the past six months. Lewis informs Stabler that Clyde seemed pretty close to all of the other gang members, and no one would have had any reason to try to kill him. Stabler brings up Benson to Lewis, and Lewis admits that he dug around once Benson's name came up, just in case she had any ties to the gang. But she's clean. Lewis also shows Stabler a photo of a man who is working on Clyde's bike, installing a GPS tracking device.
Lieutenant Tucker wakes Benson from sleep, and ends up arresting her for murder even after she vehemently denies doing the deed. At the precinct, Benson gives Tucker her story. She was home sick with the flu, but she doesn't have an alibi. Tucker thinks that the fact that no one checked in on her is suspicious. Stabler finds out from Cragen that Benson gave up her Miranda rights, which might not be the best thing, even when she's proclaiming her innocence. Stabler tells Cragen about the photo. If they find the man in that photo, that would help clear Benson's name. Cragen suggests releasing the photo to the media and let the public help find him. Meanwhile Tucker accuses Benson of being dirty, which means that her partner Stabler is probably dirty as well.
Tucker reminds Benson that she was getting psychiatric care last year and that she might have PTSD, cracked under the pressure and killed Clyde. Benson pleads for Tucker to tell her what evidence they have to link her to the crime. And Tucker says that her blood was found on the murder weapon. Benson finally realizes that she needs a lawyer. Stabler goes ballistic at Warner for tainting the evidence, but Warner is certain that Benson's DNA was on the knife that killed Clyde.
In Central Booking, Benson discovers that her attorney will be Trevor Langan, who says that her friends paid for his assignment so she can't balk at who she got as a lawyer. Members of the Death Knights are at Benson's arraignment. Her bail is set and Langan says he has to get her out of Riker's Island before any other Death Knights get a hold of her. Benson posts bail thanks to Stabler, who took a mortgage out on his house. A tip from an ex-girlfriend leads the detectives to Lawrence Grabowski, who is stuck underneath a shelf in his office. The gang might have gotten to him first. Lawrence claims that he did not do anything to Clyde and that he didn't take Benson's blood. He was only following Benson because he was hired by someone else, Brady Harrison. Harrison was convicted of a series of date rapes and was sent to prison thanks to Benson and Stabler.
Munch and Cragen finally discover the link between Harrison and Clyde. They were in Attica together, and apparently got into a fight, where Harrison was so badly beat up that he had to be taken to the infirmary. Fin and Stabler go to Harrison's place, but they don't find him. They also find that the place has already been turned upside down, presumably by the Death Knights. Stabler tracks down the gang, and Russell says that the club did go to Harrison's home, but he was already gone. Without Harrison, Benson will be the one tried for Clyde's murder.
Benson returns to her home as the detectives try to find Harrison. Harrison hired Lawrence to follow Benson into a restaurant, and Lawrence took Benson's eating utensils after she was done with them. However, Warner says that the sample she tested had Benson's blood, not her saliva. The detectives find out that there is now a way to combine blood with any DNA to create a faked DNA sample. The detectives go to talk to Dr. Joseph, who has a reputation for making these fabricated blood samples. Dr. Joseph knows Harrison and Fin tells the doctor to get in touch with him. They track down Harrison's location, and he isn't that far from Benson's apartment.
Harrison breaks into Benson's home, grabs her and threatens her with his Taser. He's convinced that Benson planned for Clyde to rape him in prison because she told him "that's what happens to 'pretty boys' in there. 'You'll understand what you put those women through.'" Benson apologizes and she tells Harrison that she wasn't aware he was going to be sexually assaulted. Harrison is ready to shoot himself in the head since he's the only person who knows the entire truth. Olivia throws a lamp and herself at him so he can't commit suicide. They struggle, and Olivia grabs his Taser and uses it on Harrison. Then Stabler arrives and arrests him. Back at the precinct, Stabler and Benson speak to Dr. Joseph about the fabricated DNA. The DNA may have put a lot of innocent people in prison as well as let a lot of true criminals go free. Now that even DNA isn't 100% rock solid proof, this changes the way the detectives go after evidence.