The tenth anniversary of 9/11 proves a wrenching but clarifying passage for Mac, who suffered a terrible loss on that day. Meanwhile, an open-and-shut robbery/homicide proves more complicated than the team had anticipated. Robert Forster and Cassidy Freeman guest-star.
When the body of a beautiful young woman is found in a stolen Ferrari, the investigation leads to a family of car thieves, but the CSIs must find the murderer before the rest of the family meets the same fate.
News of a high school house party goes viral but it ends in disaster when a balcony full of teenagers collapses from overcrowding, injuring the teens and killing a girl. During their investigations they uncover more than they had expected and the CSIs must use social media to uncover the truth about how she died. Meanwhile, Jo's final case at the FBI returns to haunt her when the suspect comes to New York and claims another victim.
When Mac is shot during a robbery gone wrong, he finds himself in limbo between life and death. As he fights for his life, the team struggles to keep their emotions in check as they process the evidence and bring the shooter to justice.