A woman contacts Mac as she has some information about a possible murder. However, before Mac gets to meet with her, she ends up dead because of the information she has shared. Mac is left with more questions and two murders to solve.
The invitation to a truck party turns deadly when the trailer crashes and ends up in the river. The team has to work out if some of the guests were the intended targets and find connections between them.
A park runner tries to escape from her killer; when her body is discovered and autopsy reveals that she has literally been scared to death, the CSIs start to experience eerie experiences. Soon afterwards, a second victim that could be connected to the case is discovered.
When a series of heinous crimes strike the city, Mac finds himself between the devil and the deep blue sea; his duty to protect and serve gets in conflict with his superior's orders concerning how to handle the media and civilians' right to know.
The newest member of the CSI team, Jo Danville, a former FBI agent, is welcomed to her new job by stumbling upon the body of a young woman murdered in the 34th floor of the building that houses the NYPD Crime Lab.