When a college student is beaten, shot to death and his apartment ransacked in what appears to be a drug-related hit, the team must track down his killers. After examining the evidence in the murdered student's apartment, the team finds traces of pure, unprocessed heroin and discovers that the victim had a female roomate who is now missing. Meanwhile, Stella's aggressive interrogation tactics with a witness threaten her police badge.

A nanny is found dead near a park while Messer is in trouble when he may have shot another police officer.

Stella and Danny investigate when a jewellery designer is found dead, wearing the eight million dollar bra he created, and investigate the model he had shot and her bodyguard. Aiden begins to take the rape case she has been working on a little too personally, and is determined to stop the man before he can rape again. Hawkes gets to go into the field for the first time as he assists Mac in investigating the death of a man who liked to climb skyscrapers.

The next case takes us back to Dr. Sheldon Hawks' past and the reasons he chose to change jobs in the medical profession. The CSI team may find it extremely difficult to find out who committed the murder of the 19-year-old woman who recently started recovering from an accident.

As the fourth season begins the team find themselves investigating something that isn't usually on the Statue of Liberty. Can a musician's life be saved before time runs out?

As the search for the taxi cab killer continues riding a cab gets very deadly. The team must figure out how to keep New York City safe.

Also Danny, Lindsey, and Flack investigate the murder of a man who made a half court shot during a game that both Danny and Flack were attending.

When a man falls 20 stories to his death, and his body goes missing after it hits the ground, with no body to process, the CSI's must treat this strange development as a missing persons case.

Danny and Mac have yet to get any leads on a cop killing when Danny gets an impromptu call from a young woman who claims she's got information about the case...