While performing on the stage, the comedian Dougie Max dies. Grissom, Catherine and Capt. Brass investigate the case and Grissom and his team conclude that he was poisoned by the expensive bottled water Innoko. When a teenager dies in a convenience store, Warrick is assigned by Grissom to investigate the case, and soon he finds that the youngster had drunk Innoko water. Grissom finds that the bottles came from the same lot, and was not a tampering case. Meanwhile, Brass asks Nick to reopen the case of Shelley Stark, who died in an accident in a bathtub and Brass did not call any CSI investigator. He has just seen her husband with a hot woman driving a Ferrari and he is intrigued, since the man was inconsolable. Nick and Sara reopen the case and find new evidences.

Henry's surprise birthday party turns into disaster when the guys discover a dead body in a shut-down, out-of-the-way barbecue joint. Back in the lab, Dr. Langston discovers that "Dr. Jeckyl" has struck again.

The crime lab reluctantly brings in imprisoned serial killer Nate Haskell after he claims to know the identity of "Dr. Jeckyll." Meanwhile, clues revealing his next and perhaps final victim are mailed to Dr. Langston.