A confused young man covered in blood walks down the middle of the street while cars pass him. The police arrive and ask him if he is alright. Horatio arrives and learns that the blood on the man doesn't belong to him. Horatio asks the man what his name is and he says that he does not know. The man says that he doesn't remember who he is. The man says that he remembers killing someone but doesn't remember who.

They bring the man to the station and Calleigh begins to examine him. Eric arrives and tells Calleigh that there are no hits on the man in the fingerprint or DNA database. Calleigh tells Eric that his tox screen came back negative. They tell each other that they think that the man is faking that he lost his memory.

Witnesses at the scene where the man as picked up are questioned. Frank tells Ryan that he is getting conflicting reports about where the man came from. Ryan says that he is going to head back to the lab.

Maxine tells Ryan that the blood found on the man belong to a man and two women. Maxine says that the victims were a family. Maxine tells Ryan that they were not related to the amnesiac.

Horatio tells the man that the blood belongs to three people. The man says that he doesn't remember who the people were. The man asks Horatio if he thinks that he killed someone. Horatio says that he hopes not. As he is taken away, the man flashes a small smirk that the detectives don't see.

Horatio learns that one of the victims is a man named Mitch Crawford. Horatio, Ryan and Frank arrive at his house and check it out. Horatio finds a man and a woman in Mitch's pool. The man in the pool says that he was there to deliver some documents. He says that he saw that the Crawfords looked like they were leaving for a vacation and decided to take advantage of the pool. Ryan says that the place is clear and that it looks like Mitch has a son. Later, Frank calls Horatio and says that the Crawford son is at a military academy.

Eric tells Boa Vista that Mitch was a financial advisor. Michael, the new technician, examines the dirt from the amnesiac's boot and finds that there are traces of TNT and molasses. Boa Vista says that she knows of a residential area that was contaminated with TNT. Boa Vista says that the area consists of a two mile area.

Eric tells the man that he is going to try to jar his memory. Eric says that he has a general idea of where he was. Eric shows the man digital street photos of the area. Eric tells the man that he also lost his memory once. He says that the memories are still in his brain and they just need to trigger them. The man closes his eyes and remembers children laughing on a school bus. Eric shows the man a picture of a school. The man says that he heard a whipping noise. Eric pans up on the digital photos and shows that the school had a flag that would make a whipping noise in the wind.

Eric and Horatio go to the Crawford's vacation home and find a bloody trail. They enter the house and and find the Crawford family bound and killed. Eric stops a tape playing the Happy Birthday song. Eric finds a the man's wallet and says that the unknown man is named Doug Benson.

Tara examines the scene and notices that Mitch was killed last. Tara asks why the killer didn't take out the biggest threat first. Horatio says that he thinks that the killer wanted to have Mitch watch his family die. Eric tells Horatio that Doug worked for the Crawfords as a handyman. Eric and Ryan look for the murder weapon and find a footprint in the flower bed near the front window. Eric tells Calleigh that he feels for Doug and doesn't think he killed the family. Calleigh tells Eric to come along back to headquarters while they try to bring back Doug's memory.