Gil Grissom and Sara Sidle come to the aid of a former colleague who is implicated in tampering with evidence; Maxine and the rest of the CSI team work the murder of a couple slain on their wedding day.
Max puts CSI on lockdown when evidence in a new murder tips Grissom and Sara to a new suspect in the crime lab; Folsom and Allie investigate a series of chilling killings at a dilapidated clown-themed hotel.
When the bodies of two Regency Romantic Festival attendees are discovered, the CSI team uncovers a shocking link between their murders and previous cases.
When a young, non-verbal boy is found hiding in a stranger's garage, the CSI team searches for his missing mother; Max receives a strange letter with symbols in silver ink that Folsom and Allie recognize from prior crime scenes.
When David Hodges goes missing, the CSI team searches for any piece of evidence that can help locate him, clear his name and save the reputation of the crime lab.
