In the aftermath of a bank heist gone bad, Mac wakes up in a submerged car with no memory of how he got there.
An urgent search for the cause of a series of deaths by radiation poisoning leads the detectives to a contaminated volume in the New York City Library. Syd recovers from radiation exposure in the hospital.
On Mac's flight to D.C., an air marshal is found murdered shortly after take off. Mac is certain the killer is on board and searches for the murder weapon.
The murder of a corporate "fixer" takes the CSIs into the disparate worlds of political corruption, personal betrayal and silicone dolls.
While investigating the death of a young archaeologist who may have unearthed the answer to one of New York City's oldest murder mysteries, the CSIs discover anything can be purchased on the Internet, even someone else's life.
When three defendants are gunned down on the eve of their trial, Mac is forced to make good on a promise he made to a reluctant witness. Meanwhile, Adam's job is in jeopardy due to the budget cuts and Mac and Stella must come up with a way to save it.
Investigation of a floating crime scene leads the team into the world of "SecretU" an art-house world of true confessionals where 20-somethings divulge their darkest secrets with deadly results.
The team tackles their most unusual case yet: two murder victims within two weeks both named 'Mac Taylor.' Now, Det. Mac Taylor, and 15 others with the same moniker must determine the killer's motive before they strike again.
When an unidentified body is discovered inside a crushed car, the CSIs must extract the bones in order to identify the victim and catch a predator.