Two geocachers race to reach their goal first, but instead of finding their intended treasure, they discover a suitcase with the naked body of a young girl inside. Benson and Stabler are brought on the case, and the detectives have to break up the ensuing argument between the two geocachers over who found the suitcase first. Geocaching is like high-tech treasure hunting, and there are websites devoted to giving clues to where these caches are hidden. They don't think that the dead body was supposed to be the cache. When asked who put together the clues for their current hunt, the geocachers say it's someone called the Master Baiter. His website contains a video of his latest hunt, based in the subway system. His IP address is traced to a store on Staten Island called the Garb Barn.
Benson and Stabler go to the store to investigate, with Benson loudly paging the "Master Baiter" on the store PA system. The request gets some nervous giggles from the employees but one of them takes off running with the detectives in hot pursuit. The employee says that she didn't plant the suitcase. She was only there in the tunnel to get the shot, but a train passed by once and ruined one of her takes. The video footage reveals that the suitcase was thrown off the train.
The train was an express to Florida, and the victim is IDed as Emily Keefe, who had a one-way ticket to Tampa. The train's departure was delayed because of equipment problems, and it's suspected that the perp took advantage of the late train to find and kill Emily.
Emily's parents are notified of their daughter's death, though her stepdad wonders why she wasn't with her dog at the time, because she never went anywhere with her dog. Emily had a wild side, hanging out with the wrong people, but then she met Owen, who was a nice guy but lost his job on Wall Street. He didn't seem to care that he was unemployed, and he spent all of his time partying and sailing. The detectives give Owen a visit, and, panicked, Owen tries to flee on an inflatable raft. Stabler shoots at the raft, stopping Owen's attempt at escape.
In for questioning, Owen is told that Emily was killed. He's surprised but says right away that he didn't do it. He ran from the police because he was smoking a joint and didn't want to get caught. Drugs are found on his boat, but no evidence that Emily had been living there for awhile. Owen confesses that he's a dealer, and that he was sailing from Tampa with the drugs when Emily was found. Owen gives them the address to Emily's apartment.
Benson and Stabler search the apartment, finding Emily's dog and also a number of jewelry gift boxes from Tiffanys. Her computer reveals her profile on a website called Tasty Sugar. They go to Ad-Vance United, the company behind tastysugar.com. Lizette, an assistant with the company, tells them that the website is like social networking with a romantic twist. Her boss, Vance Shepard, is told about Emily's murder, but Vance refuses to give up any of her personal information without a warrant.
Emily's profile appears to have been wiped from Tasty Sugar, but the tech uses the Wayback Machine website to find a copy of her profile. Her profile also states that she can do double-dating with another girl named Pamela. Stabler posing as a client, meets Pamela, and it's learned that the Tasty Sugar website is basically a place where sugar daddies can meet potential sugar babies to spend all their money on. When Stabler asks about Emily, Pamela locks that down because Emily was stupid and fell in love with someone. Which turns out to be Vance.
Vance is brought in for questioning and he's eager because he has nothing to hide. His home life is pretty much a wreck. His wife Joyce is a hypochondriac who "faked" having breast cancer for attention, going so far as getting a mastectomy. His daughter Chantel is starved for attention and isn't getting it from her dad. Vance says that he loved Emily and wanted to be more than her sugar daddy, but they had a fight and he ended up breaking up with Emily on the same day she was killed. Joyce tells the detectives later that she thinks Vance is immature and combative when he doesn't get his way. He was never physically abusive but was mentally abusive to her and to Chantel.
Vance sticks to his story that Emily ran out of his apartment and that he stayed at home for 90 minutes before going to dinner with his assistant, Lizette. Before Vance can be questioned further, however, his lawyer (Dwight Stannich) arrives with video evidence that Emily was alive and well when she left Vance.
ADA Paxton is furious that they have to release Vance, and there's a discussion about the difference between prostitution and having an actual escort service, and the difference appears to be the amount of money and gifts exchanged. Paxton suggests going to talk to Lizette the assistant again, even though the detectives say that she knows nothing. Paxton (with Benson and Stabler in tow) goes to Ad-Vance, and Paxton puts pressure on Lizette, pointing out that her impressive boob job (a gift from Vance) would make her a very grateful girl. Grateful enough to do anything that Vance told her to do. Vance arrives, upset that someone is out to harass one of his employees. Paxton points out that they're going to search through all the surveillance footage at Grand Central and eventually find Vance standing on the platform, and it's only a matter of time. Vance tells them to leave, but Paxton says she's already done her job. It wasn't Lizette she wanted to make worried; it's Vance.
SVU is about to sort through hours of video from the train station when Lizette arrives and says that she can't lie for Vance any longer. She and Vance had dinner, but he arrived late, and he was out of breath and distracted. His shirt was bloody. He said that he was hit by a taxi and gave the shirt to Lizette to get dry-cleaned. Lizette still had the shirt, and she thinks that Vance killed Emily. After Lizette's confession, Vance is arrested.
Vance is in interrogation and he confesses to killing Emily. He gave her everything and she still went back to an old boyfriend. Paxton realizes that Vance doesn't have his lawyer with him and tries to stop the interrogation. Vance says he doesn't need a lawyer, and he just wants to confess to the crime. Paxton just wants to do everything by the book, which means that he has to have a lawyer present even as he's saying that he killed her.
At the arraignment, Vance pleads guilty but his lawyer pleads not guilty. The argument being that it was a crime of passion and Vance can't be held responsible for what he did. SVU is combing through the video footage at Grand Central and while there is evidence of Emily at the station, there's no evidence of Vance. However, there's something strange about the images of Emily, because in one shot, it doesn't look like Emily.
Chantel killed Emily because she was jealous that someone around her age was spending all this time with her dad while she and her mom were basically being ignored. Vance found Emily's body and immediately decided to take the blame for her murder, because he thought that was how he could finally show Chantel that he loves her. He takes the blame for making Chantel into a cold-blooded killer.
Chantel posed as Emily when getting on the train, but then the train was delayed, which made her nervous enough to dispose of the suitcase containing Emily's body. Vance asks to see his daughter one more time, and he hugs her, but she ends up stabbing him in the neck with a pair of scissors, saying that he'll never break another promise to her again. Vance bleeds to death, with Benson and Stabler in shock, and Paxton on the brink of crying.