A working girl gets kicked out of a coffee shop where she wanted to use the restaurant. She and her friend exchange words with two guys on the street. The woman warns her friend to be careful and leaves. Across the street she meets another woman who gives her a backpack. She asks for cash but the other woman won't give it to her. The other woman seems to be her sister and is worried about her and wants her to stay with her. She won't.

The woman from scene 1 goes into a bar. She has a date.

Later, she runs across a field and behind a dumpster where she calls her sister and says someone raped her and tried to kill her. She wants to stay with her but is attacked from behind.

Benson tells Fin that McGrath is being respectful for now. Meanwhile, Daria has shown up to report her sister's disappearance. Benson sends the desk sergeants who took the report away so she can talk to Daria herself.

The cops listen to the voicemail. Daria says that usually Tanya calls asking for drug money so she didn't pick up the phone or listen til this morning. She says that Tanya is homeless and a survival sex worker. Benson asks if Daria knows anyone who Tanya hangs out with or works with.

A woman at a group home is surprised the cops care. A bunch of other girls are unhelpful but mention a dealer named Beauty.

Beauty is the girl from the first scene. She says that she has taught T how to survive. She saw her last night. They were supposed to meet but T never showed up so she figured she was just high.

The bartender gives the cops the backpack Tanya left with him. Daria IDs it. Country, the bartender, looks out for Tanya. One of the girls shows up and says Beauty is also missing. Beauty went to score and never came back. They don't know who her dealer is but have her bag. There's a compact in it from Beauty's grandma. Benson has a bad feeling about this. She wants Velasco to check to make sure there aren't other reports of missing women that have been ignored.

Rollins and Velasco speak to a desk sergeant who says the detective went home but has a bunch of missing persons reports for them. There's at least 10 photos and three of them look like Tanya/Beauty.

Benson wants to look into who filed the initial reports. No one knows. The phone numbers no longer work. The detectives did nothing and no one was looking for these girls.

Benson and Fin visit the ME's office. He has two victims that match the profile. Both girls were strangled and raped. However the ME doesn't think it's a serial. The second girl was missing her intestines and liver.

The cops have a warrant for Country's knives. He's angry. The cops convince him to come down to the station. He has a record for assault. He claims he was closing up all night. Benson has street cam footage of his station wagon. Country says he went for a drive. Footage shows he had a passenger going north but alone half an hour later. He insists he just looks out for the girls. Benson says lying to him might be a parole violation if he doesn't talk. Country says he dropped Tonya off at her date but didn't see the guy. When Tonya comes back he wants an apology. Benson wants the address.

Valesco thinks Country made this up. Rollins doesn't think he' d bother. A little boy with a skateboard sees they are cops and tells them a vampire lives in the building behind him. He saw Tonya, maybe, but won't talk more in front of his friends.

The cops break into the building. There's a bad smell. It's dark. There appear to be organs in jars. They find a bunch of decaying bodies, they look like skeletons. Rollins is freaked out.  They find Beauty and Tonya on slabs in another room.

Benson has arrived and is disgusted. She wants to get autopsy rape kits. 12 victims plus Tanya and Beauty. Mummfication should preserve some DNA and fingerprints to ID the bodies but not the killer's DNA. McGrath comes too and doesn't particularly want to hear the details of how the bodies were mutilated. Benson takes him outside to talk.

McGrath thinks Country wanted to be caught. He is disgusted and wants the case made now. As far as he is concerned this is pure evil.

Velasco says he had to look at the bodies when he didn't want to. Benson admits she has never seen anything like this in 20 years and anyway you never get used to it.

Benson and Fin show the bodies to Country who is also disgusted. Benson tells him he'd better talk. He recognizes one of the girls. He drove her to a date in the same area as Tonya. Fin doesn't believe Country is innocent. Country starts crying he is sorry. Velasco interrupts. The ME has something.

ME says all 12 victims were sex workers. All strangled and some stuffed with their own clothing. Got two hits from missing persons reports and were able to ID them. One of them had a charm bracelet with her name and birthdate on it. They haven't been able to get in touch with families. But the two girls they ID'd were killed while Country was in jail so Country is innocent!

McGrath and Benson have a press conference and offer a $3500 reward for info that leads to an arrest.

Velasco finds out that the building owner died a decade ago. The little boy, Jamal, comes up to them again. He saw the "vampire" and knows he's white and has a pickup truck.

Benson tells Daria she doesn't have to look at the body if she doesn't want to. She has to see her. She has brought a photo of the two of them. The ME tells her she wants to remember the photo, not the body. Daria sobs as she looks at the body, then grabs the photo and hugs it to herself. She tells Benson she has to go.

Benson has never seen the photo technique. The ME explains that the brain doesn't need to retain these horrific images and that the victims should remember their loved ones as they were in life.

One of the victims' mothers has a grandson with Autism who she says she can't send out of the room because he'd get too anxious but he isn't listening. Her daughter met a man at a carnival and was happy for a minute. She ran off with the guy. The boy remembers the exact date. And the truck's license plate (they did this once on Cold Case) Mommy told him not to tell anything.

Rollins and Velasco go to Jersey to pick up the suspect, who insists he didn't do anything. His mother insists on coming too.

The timeline fits. Benson observes the mother and tells Velasco to give her a  cup of coffee and question her.

Tracy denies being in New York Sunday night but they have proof his truck was there. He claims what happened was sick but denies it was him. He might have bought heaters for his mother.

Tracy's mother claims he has always been super quiet and couldn't have done this. She's sure he was lying about seeing a girl. She tells Benson that Tracy is a loser.

Tracy denies knowing the girls. He likes classier girls. Benson comes in and Tracy insists that his mother knows nothing about him. She sends the other two out of the room and he says his mother is a lonely old woman. Benson tells him that his mom says he's soft and doesn't talk to girls. She asks him about Meredith and says that Meredith felt sorry for Tracy and was out of his league. Tracy denies that. Meredith loved him. Benson asks if he killed Meredith when she tried to leave. He denies murdering anyone. Benson says his mom said that he was incapable of murder and she agrees with her. Tracy says she doesn't know him either. Benson says the guy she is looking for is methodical, intelligent, organized, and picked women t hat nobody would look for and found a location that he kept hidden for 10 years. Tracy says so you think this guy is smart? Benson says that this guy is special and when they find him they'll make documentaries about him. Tracy said he heard the building owner was dead. Benson says okay this guy is lucky. Tracy says the guy is very smart. Benson says he found an abandoned building where the owner happens to be dead. Tracy says the killer pretended to be a buyer and poisoned the owner with tea. Benson says that is a good plan. Tracy laughs that it was and it was his plan. Tracy says he killed all of them. They were HIS girls and she disturbed his work. He says Tonya screamed for her sister. Beauty couldn't stop shaking.  He kept Meredith alive for days but he killed them all. Tell his mother that.

Benson finds out Tracy will plead guilty to a dozen homicides. Fin says FBI is checking into it and might file federal charges anyway.

The ME has ID'd several more victims and will keep working til he finds out who they all were.

Beauty's grandma comes in. Benson turns off the video monitor. She stares at the photos of Beauty.