When a young mother is found dead in what appears to be a suicide, the CSIs find evidence to the contrary, thus opening up a homicide investigation. Murder is immediately suspected, but without any bodies, it is difficult for the team to ascertain what happened. The CSIs are called to a house in which the inhabitants, a family of four, have gone missing, and large pools of blood cover parts of the floor. As the team investigates further, they find out that the mass suicide didn't go as the cult leader planned. It is soon discovered that the group is a cult, but when Grissom and Catherine find the cult's headquarters, they find the members all dead from what appears to be a mass suicide. The CSIs are called in when a homeowner finds a disheveled group of teenagers dumping a body in his yard. Suspicion quickly falls on the victim's husband, but the blood-spattered evidence tells a complicated story. The CSI team investigates the case of a woman found dead on the staircase of her suburban home. Story by : Josh Berman & Carol Mendelsohn Meanwhile, Grissom, Catherine, and Sara uncover two murders among the immigrant laundry workers from the same hotel.
Nick and Warrick investigate the suspicious murder of a young movie star who is found dead after a night of partying in his hotel suite. Meanwhile, Grissom determines there was an accomplice in Nick's kidnapping. The team tackles three separate cases: Grissom and Nick investigate the case of a murdered couple found in bed in a suspicious trailer explosion Catherine and Warrick look into the death of a stripper discovered dead in the worst part of town and Greg and Sara try to find the killer of two bodies found decomposed after spending five days in the trunk of a car. Story by : Naren Shankar & Carol Mendelsohn In the episode Rashomama, the story is told in flashbacks by different narrations of involved characters and witnesses, a reference to the Japanese film Rashomon. Also this season, Nick hunts the head of a civil war reenactor ("Way to Go"), Grissom investigates the death of a psychic ("Spellbound"), and Sara comes face to face with her toughest adversary yet ("The Unusual Suspect"). Meanwhile, Grissom and Willows reunite in order to investigate their toughest cases yet, including the death of a movie star ("Room Service"), a corpse discovered at a suburban home ("Bite Me"), a mass suicide at a cult ("Shooting Stars"), and an apparent suicide ("Secrets and Flies"), as Nick comes to terms with his PTSD ("Bodies in Motion"), and later tracks down a missing child ("Gum Drops"). Brass, now partnered with Sofia Curtis, finds himself caught in a shootout that leaves one officer dead, and a Latino community enraged ("A Bullet Runs Through It"), before finding himself critically injured in a hostage standoff ("Bang-Bang"), in the sixth season of CSI.