Meet the little known and even less understood heroes of police work in Las Vegas - the forensic investigators, as they work to untangle the evidence behind the yellow police tape. Wednesday, 5.30am: in an off-the-strip, somewhat-out-of-the-way casino, a room service waiter rounds a corner and stumbles across a killer, and a corpse. Homicide detective Jim Brass summons Grissom and company to the scene. As Brass follows his instincts, Warrick and Sara follow evidence the killer left behind, and Nick and Catherine investigate a murder that's fifteen years new. Although focused at first on the perpetrator's deadly double-tap signature, Grissom will soon make the most troubling discovery of all: the inexplicable interest of FBI agent Rick Culpepper.