During a typical morning rush hour in downtown Miami, an unseen sniper chooses three victims at random and opens fire, killing each with a single shot to the head. Horatio and his crew rush to the scene, which is quickly mobbed by TV news reporters eager to spin the murders into a national story. The initial investigation doesn't reveal much, as there were no witnesses and little evidence remains. But the case heats up when the sniper strikes again, killing two more innocent people.

A nude man is found tied to his bed, having suffocated on a rag stuffed in his mouth while he was being sexually assaulted. Meanwhile, while investigating the murder of a crematorium owner, the CSIs discover dozens of bodies that were never cremated.

Horatio is approached by a parolee he helped put away several years ago, who begs for his assistance in finding his missing teenage son. As the investigation gets underway, Horatio discovers that the boy may be planning a deadly assault at his high school. Meanwhile, as Speedle investigates a man's death, the victim's flirtatious girlfriend, who was there when he died, tries to play on Speedle's obvious attraction to her.