Assemblyman Danilo Zamesca, an avid anti-drug crusader, is found murdered in his car in a remote location in the desert. Nick and Catherine process the scene and find a torn photograph on the ground and drugs in Zemesca's car. In the photograph, Zemesca is seen snorting heroin.
Using bullet casings and fingerprints found at the scene, the CSIs link Thomas Simon, the West Coast's biggest illegal drug supplier, to the murder. However, when Brass goes to Simon's strip club to arrest him, he learns that Simon hasn't been seen in weeks.
Brass, Catherine, and Keppler meet with the Undersheriff, who pressures them to catch Simon. Keppler suggests using reverse forensics, a strategy in which a crime scene is faked and a "suspect" arrested, in order to lull Simon into a false sense of security and expose himself. However, in order for this strategy to work, as few people as possible must know about it - Catherine quickly realizes that this means deceiving the other CSIs on her team and expresses her reluctance. The Undersheriff orders her to do it.
Sara is called to a hotel room where a woman lies dead. She finds heroin and drug paraphernalia in the room, and David suggests drug overdose as a possible cause of death. Sara and Sofia are puzzled by the large amounts of food in the room.
Catherine assigns Nick and Warrick to a stolen motor vehicle case in order to get them out of the way. Brass recruits a drug dealer to play the suspect in the fake crime. Catherine and Keppler cover the windows of a lab in order to create fake evidence away from prying eyes. They have recruited an undercover police officer to act as the "victim", and they spray a car with blood that the officer has donated. Catherine notes that without brain matter or bone fragments from the victim, the crime scene will be less than perfect. Keppler tells Catherine that a third CSI must be at the scene in order to give legitimacy to the investigation.
Greg joins Sara and Sofia at the dead woman's room and processes her car. He discovers that the victim is Monique Carter and that she lived in a good neighborhood some distance from the hotel. During Monique's autopsy, David discovers a wound on her head that suggests she was murdered.
At the lab, Catherine learns that the drugs from Monique's hotel room are the same as the drugs found in Zemesca's car. Catherine then forces the lab tech to leave his station and takes a sample of the drugs. Meanwhile, Keppler test-fires a gun in the ballistics lab and takes the bullet. Catherine and Keppler then create a crime scene, one that looks almost identical to the Zemesca crime scene, in a remote location in the desert - they plant the drugs and the bullet, take photos of the "victim", Ezekial Holstein, in the car, and have the "suspect" reenact the crime. As he does so, Keppler realizes that the real killer originally intended only to hand Zemesca the photograph and killed him only after the meeting did not go as planned. As he describes the killer's actions, Keppler refers to the killer in the first person.
As Brass arrives, Keppler anonymously dials 911 to report the "murder". Brass responds to the radio call, confirming that himself, Keppler and Catherine will attend the scene. Catherine then calls Doc Robbins and asks for permission to move the body before the coroner arrives; Doc Robbins, who is in the middle of an autopsy, agrees and tells her to send the body to a mortuary. She also calls Warrick and asks him to join her at the scene; she specifically asks that Nick not come with him.
Sofia questions Monique's hotel manager and learns that a man was living with her in her room for some time. Greg also discovers that someone made phone calls from Monique's cell phone after her death.
Nick sees evidence from the fake crime scene and mistakes it for evidence from the Zemesca case. Hodges corrects him, and Nick begins to suspect that something is not quite right. He asks Doc Robbins, who is sewing up Monique Carter, about the body from the Holstein case and learns that it has not yet arrived at the lab. Nick then recognizes a tattoo on Monique's arm from the photograph found at the Zemesca crime scene and realizes that his crime scene and Sara's are related.
As Sara and Greg process Monique's car, they learn that she was a disbarred lawyer. Nick comes to ask about a possible Zemesca/Monique connection and notices that the exposed foam from Monique's car seat matches foam found at the Zemesca crime scene. Nick then tells Catherine, Keppler, and Warrick of the connection, hypothesizing that Simon drove Monique's car to the Zemesca scene. However, Catherine informs Nick that fingerprints from her crime scene point to a drug dealer named Edwin Dennison, and that Dennison appears to have killed Zemesca as well. Dennison is arrested and the Undersheriff announces to the press that Dennison has confessed to Zemesca's murder.
Warrick grows suspicious after examining a bullet found at the Holstein crime scene - he notes to Keppler that the bullet looks too clean to have passed through a glass window and the victim's head. Nick's suspicions increase when he tries to examine the Holstein case evidence and is ordered by Catherine to back off. Nick then gathers Warrick, Sara, and Greg and tells them his concerns about Catherine's investigation. The other three CSIs also recall Catherine and Keppler engaging in various suspicious activities throughout the course of the investigation, and by the end of the meeting, all four agree that they cannot trust Catherine or Keppler and must figure out the truth for themselves. They track down evidence from the Holstein case and process it; they quickly discover glaring inconsistencies in the evidence and realize that the crime scene is a fake.
Brass returns to Simon's strip club and finds that the reverse forensics worked - Simon is at the strip club, no longer in hiding. Brass arrests him. However, the Undersheriff never cleared the operation with the District Attorney, and the DA refuses to charge Simon with Zemesca's murder, declaring that she cannot tell fact from fiction in the case.
Catherine and Keppler come clean to the other CSIs and tell them about reverse forensics. The four CSIs express feelings of frustration, anger, and betrayal at their deception. Catherine asks them to focus on nabbing Simon for Monique's murder.
The CSIs learn that phone records from Monique's cell phone point to Simon, as do fingerprints from Monique's hotel room. Simon is arrested for Monique's murder. The media reports that Zemesca and Monique were college classmates.
After the case is closed, Catherine asks Keppler about his tendency to refer to killers in the first person. Keppler replies that it helps him to identify with the killer, as identifying with the victim clouds his judgment.
Nick leaves the lab, clearly still upset about the day's events.