The whole team must investigate a crime where a husband and his porn star wife were murdered execution style. Things get personal for Catherine when Grissom talks to her about her evaluation. Brass believes that Sara may have some type of problem.

Catherine and Sara deal with the death of what at first seems to be a transvestite. Later during autopsy they find out that the make-up he seemed to be wearing was actually facepaint, he was a clown. Grissom, Nick, and Warrick deal with the death of a man in a homeless area. They found out he worked in a recovery center for drug users.

Two men are found murdered after scamming Sam Braun's casinos. Grissom and Warrick investigate after Catherine is thrown off the case. One of the suspects is the son of a man Braun caught cheating. Nick gets the promotion that Sara coveted.

A wild night in Las Vegas has the CSIs simultaneously investigating four fatalities. Greg Sanders' first day in the field has him assisting Grissom's investigation of a fatal nightclub shooting. Meanwhile, Catherine probes into the death of a stripper found dead in a hotel room, while Sara and Nick look into the strange case of an "alien" body found near Area 51.