Using the photos, Stella and Flack retrace the woman's last steps. They find lip balm they suspect belonged to the victim. They follow a set of tracks which leads next to an apartment building. Jimmy, the doorman, recognizes the woman as Estelle. He states Estelle takes pictures of the park daily with her boyfriend Keith. He says Keith wasn't with her the day she died. After they ask Jimmy if Estelle had any other visitors, he says an older guy visited Estelle late at night.

Mac brings in Keith for questioning and shows him the photo of him found on Estelle's camera. He says the last time he saw Estelle was the day before yesterday. Keith admits he had an argument with Estelle. Mac tells him about an older gentleman that visited Estelle. Keith states that Estelle was acting weird recently.

Sheldon says the dried blood fleck belonged to multiple donors. He finds a match to a man named Billy James who has a record of assault and battery. Sheldon and Flack visit Billy at the tattoo parlor he works at. The detectives inform Billy that Estelle is dead. They notice a scar similar to Estelle's on Billy's wrist. They tell him that they need to confiscate all of his tattoo guns and equipment for evidence.

Estelle's parents arrive to identify their daughter's body. They say Estelle didn't even live in New York for a year. They tell Mac they last spoke to Estelle two days ago when she told them that her photography was going well.

On a pig, Sheldon tests the puncture wounds that the tattoo tools produce to see if it matches the wound in Estelle's neck. Afterwards, he tells Stella that none of the tools are capable of puncturing the carotid artery. Stella says Billy's alibi checks out.

Sid tells Mac that he recognizes the scar on Estelle's wrist. He explains that the scar is a result of a cutting ceremony performed by a cult of sanguine vampires. He explains this group believes that through blood exchange they reach a higher place. He states that the ceremony is a consensual. Mac states that Billy James and Estelle's father had similar scars.

Danny and Flack investigate Estelle's apartment and find vampire literature. Danny says he doesn't understand the recent vampire craze. Inside Estelle's fridge, Danny finds a roll of film. He processes the pictures and discovers that it contains photos of a gathering of people including Keith and Billy. They notice an older man in two separate events. Stella notices a blade on the table in one of the photos.

Mac meets with Estelle's father Mr. Christensen at his hotel and shows him the photos that Estelle took. After Mac says he knows about his scar mark, Mr. Christensen admits he knows the older man as Joseph Vance. He explains he met Joseph at a haven, which is a meeting place for vampires. He says Joseph is the master of the New York haven and was asked to watch over Estelle.

At the lab, Danny discovers that the object on the table is blade shaped in an ankh, which is an Egyptian symbol for eternal life. They wonder if the object was used to kill Estelle.