An 18-year-old girl and her four-year-old sister are the only survivors when a suburban Las Vegas family is brutally slain. All evidence indicates that the family was butchered by the members of a cult. But in the course of his investigation, Grissom (William L. Petersen) -- who was the first authority on the scene after the surviving girls summoned help -- suspects that the solution to the crime may be even more disturbing than he wants to believe. ~ Hal Erickson, Rovi