Stabler and Benson are called to the scene of a woman who has been shot after receiving slashes to the neck and genital area. Benson finds a proof sheet, which shows the victim was probably a model or an actress. Warner points out that there are saliva marks near the victim's open wounds. Benson also finds a dead bird in the woman's purse.
After finding a VIP stamp to an after-hours club on the victim's wrist, Stabler and Fin hit the streets and interview the wrangler to the club, Oscar. Oscar looks at the pictures and identifies the girl as an aspiring model, Natalie Bleers, and shows Stabler and Fin the flophouse that she crashed at, along with other modeling hopefuls.
Fin and Stabler discover that Natalie had a twin sister Pamela and they bring her in for questioning. Pamela swears she would never hurt Natalie and that she was her manager. She said Natalie had been hanging out with a hip-hop artist, Gots Money, and Pamela is sure he is the one who murdered her sister.
Warner tells Fin and Stabler that Natalie's slash marks were the work of a tiger. Warner shows up and points out that the bird in Natalie's purse was illegal and Stabler comes to the conclusion that Natalie was participating in illegal wildlife smuggling for Gots.
Fin and Stabler discover that Gots has a tiger and immediately link it to the death of Natalie. Gots swears that it was Natalie who was involved in animal smuggling and she got him the tiger. Benson tells Fin and Stabler that Gots is telling the truth; DNA evidence proves that another tiger mauled Natalie and supports Gots story. Gots says he'll lead Fin and Stabler to the people who are in charge of the animal smuggling ring, but Stabler will have to be undercover.
Stabler goes undercover as Mike, a customs agent looking into smuggling animals. He spots a tiger and gets a piece of its hair that later matches the tiger DNA found on Natalie's body. Cragen is upset when he finds out Stabler went undercover without telling him. Agent Culky from Fish and Wildlife comes in and tells Stabler to back off her case against Busheto, the kingpin in the smuggling ring. Her department has been investigating him for 14 murders and they don't want Stabler to jeopardize their case.
Agent Culky accompanies Stabler to Gots' residence, where neighbors report hearing loud noises. There, they find caged hyenas and a room covered with blood. Agent Culky and Stabler believe Busheto got wind of Gots' involvement with the cops and unleashed his animals to do the dirty work.
Stabler goes back undercover as Mike and talks to Busheto about animals. Busheto welcomes "Mike" to sit down and enjoy a meal with him... the meal being the tiger that killed Natalie. Busheto offers Mike the job of helping smuggle in a white gibbon monkey. Before Mike can take the job, he has to give up his wallet and his cell phone.
"Mike" is ready to take on his assignment. But, first, Busheto ties a GPS system to his wrist and threatens his life if Mike isn't who he says he is. Meanwhile, Benson tells Kathy about Stabler's undercover assignment and Kathy gets ready to leave Stabler for good. Benson feels terrible for having to give Kathy the news and tries to talk her out of taking any drastic action.
Busheto and his partner catch Benson at Mike's place and demand to know who she is. She goes into character and acts like a prostitute that Mike just hired for the night. Busheto and Tybor usher her out of the room at gunpoint.
Busheto takes Mike to a house to pick up a cage. He tells Mike to get out of the car and then shoots him twice and drives away. People see Stabler on the ground and call for the police. Benson is the first to be by Stabler's side as he slips in and out of consciousness on the street.
Stabler makes a full recovery and Cragen leaks to the paper that a customs agent was shot and killed in an animal smuggling ring. That way, Stabler's cover is not blown. When they return to Busheto's headquarters, they discover the whole place has been cleared out. Back at the SVU, Stabler arrives, eager to help out in the investigation.
After the detectives get wind of the white gibbon coming in from Jakarta, they head to the airport. Fin and Benson survey the scene from below and Cragen and Stabler survey from a separate room on the second floor. Stabler spots an anxious man with a basketball at the Jakarta gate and is sure the monkey must be in the basketball.
The detectives follow the man with the basketball to a warehouse in Queens, where they find a money transaction about to take place between a businessman and Busheto. When Busheto spots Stabler, he throws the monkey at Cragen and runs. Stabler takes after him, as Benson goes after Tybor. Fin instructs the businessman to run away from the scene.
Stabler corners Busheta and informs him he's going to be caged for a very long time. Meanwhile, Benson watches as Tybor hangs on to the side of the building. He tells Benson he's an undercover agent working for Fish and Wildlife, insisting he has a wire. Tybor's job isn't done. Stabler wants to know if there is anything he can relay to his family; Tybor says his family left him long ago.