Follow the investigations of a team of NYPD forensic scientists and police officers identified as "Crime Scene Investigators".
The CSIs investigate when a fire chief - a friend of Mac's - is killed in a blaze that used the same technique as a recently paroled arsonist.
The CSIs rush to stop serial arsonist Leonard Brooks after he begins using fire against people from his dark past.
A homicide on the Brooklyn Bridge leads Mac and Jo all the way to San Francisco to find a missing teenage girl, but they are not sure if she is dead or alive.
The CSIs race to catch a shooter when Lindsay is injured during the attempted murder of a political candidate, and the events in the aftermath lead to a child's death.
Mac investigates a 20 year old case when the prime suspect is found murdered on the anniversary of the boy's disappearance.
The CSIs investigate a twisted fairy tale when a woman in a ball gown is found at the bottom of the pond outside Belvedere Castle in Central Park.
When a psychiatrist's patients are being systematically murdered, the CSIs are forced to play along in a game of Clue in order to catch the killer.
The CSIs must delve into the high-pressure world of an elite prep schools when a student is murdered while studying for the SAT'S. Meanwhile, Lindsay returns home to Montana to visit her father and deal with some issues from her past.
When Det. Lovato's cover is inadvertently blown, the CSI's investigate the Latin street gang she infiltrated when undercover.
The CSIs investigate a 1920s-inspired speakeasy when one of its owners is murdered and $10,000 goes missing. Meanwhile, Adam spends his day off in an unexpected way.
The CSIs are confronted with a puzzling mystery when two different victims are linked by the same unusual weapon.
When a beloved off-duty NYPD officer perishes in a robbery, the CSIs use the art of interrogation to break down their suspects and get to the truth.
The CSIs investigate when a masked man is found at the bottom of a notorious skyscraper known for its history of mysterious deaths. Meanwhile, on her day off, Jo runs into a stranger with a surprising link to her past.
When a young pizza maker is carjacked, the CSIs must determine what the perpetrators were really after.
Mac and the team partner with D.B. Russell to outsmart Christine's kidnappers before they run out of time to save her life.
On Valentine's Day, Mac and the team tackle three twisted tales of love gone wrong.
Community unrest over the police shooting of an unarmed man forces Mac and the team to move quickly to solve the case.