When a suburban soccer mom is murdered, the CSIs uncover her family's dark past, while Delko continues his undercover mission. At the end of the episode, Caliegh confronts Delko of what's going on and an explosions happens soon after.

A serial killer taunts the CSIs by leaving them cryptic hints, and the longer it takes them to decode these puzzles, the higher the death toll rises. In the opening sequence the daughter of the first victim can be heard singing the "Ashes ashes all fall down" chorus from the Grateful Dead's "Throwing Stones".