A legendary icon on the Vegas strip, Margot Wilton, is attacked with a blade in her bedroom but survives. When the CSI team is called to the scene, they discover the attacker has been watching his victim from within the house for sometime but oddly they find no DNA or prints from the attacker. Soon a high-profile community activist is attacked in the same manner as Wilton except this victim is killed. The husband of the newest victim says his wife was also attacked, just a few months prior, with a blade but survived. The attacker kept repeating the same phrase "I know what you did, confess!". His wife acted as if she didn't know what the attacker was talking about but the team soon finds she was cheating on her husband while posing as a model citizen. Based on clues the attacker left at Wilton's home, Langston knows she has something to hide and goes to speak with her but she refutes the assurtion that she is not telling the whole truth. Against Langston's advice, she returns to her home and the Mayor of Las Vegas threatens Brass and the CSIs with harrassment lawsuits if they come near her. They know she is in danger but need the greenlight from Ecklie in order to protect her. Meanwhile, in Wilton's house, the mystery attacker appears and tells her that he gave her the chance to confess but she didn't take it. She struggles with the attacker and when the team hears gunshots they rush in. Wilton is badly bleeding and the attacker has vanished into thin air once again but has left behind the proof of Wilton's secret. She murdered her disabled son before she became famous because he was a burden on her career. The team also finds the body of a local EMT who had fresh healing blade wounds on his body. It turns out, the EMT who had recently been praised in the press as a hero for saving children from a burning building was actually the one that was starting the fires. Langston and the team know that the killer is punishing those that don't confess to their crimes and must find him before he kills again.