When Willows works with the FBI again after a professional hit occurs at a law firm she recommended to her friend, the CSI team identifies shocking similarities at the crime scene.
The 12th season begins with the lab getting a new supervisor (Ted Danson), who helps the CSIs investigate multiple shootings and stabbings on a public tram, with one witness and a lot of questions.
A string of deaths,start a bet among the CSIs as to whether they've "hit for the cycle" - a homicide, a suicide, an accidental and a natural death all in one nigh
While investigating the murder of a convicted ex-cop, the CSIs stumble upon a list in his prison cell with names of several individuals he believed might have been his wife's true killer.