Horatio investigates the death of a man who accidentally inhaled a lethal combination of chemicals in a neighboring house after he went inside to retrieve his cat. Elsewhere, a resident of a retirement community is found dead in a pool of blood, an apparent victim of a vicious attack.

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 and his team investigate after a Russian immigrant is stabbed to death in a peep-show booth, and the only witness to the crime is the stripper who was performing for him.

The investigation into a drug heist offers brief glimpses into the private lives of the CSIs, whose nerves are on edge when they become suspects in the crime they're trying to solve. A police convoy headed across town includes an unmarked truck filled with confiscated drugs being taken to an incinerator to be destroyed. The trip ends abruptly when thieves hijack the vehicle, kill its driver and shoot Speedle, who was riding shotgun. It's hard for Horatio when the media draw comparisons to a similar case several years ago in which his brother, an undercover cop, was killed. But it's worse for his team when Internal Affairs decides that one of them tipped off the robbers about the delivery.