Warrick's appearance at the preliminary hearing on a rape and murder case goes terribly wrong when the only piece of evidence is thrown out on a technicality. Grissom and the team have 24 hours to make the case with new evidence or the killer will go free.

A woman found murdered in her home. Her resemblance to Sara causes Grissom to take a personal interest in the case and forces him to examine the decisions he has made in his life.

A mutilated female body is discovered tied to the undercarriage of a bus carrying prisoners from a women's correctional facility after a severed arm flies out from beneath the vehicle and strikes a car. Catherine leads the investigation and at first believes the woman was escaping, but the evidence increasingly points to murder. Back in town, Warrick probes the death of a gambler who was stabbed multiple times in his brother's kitchen.

A roller coaster runs off track leaving 6 people dead. The CSI team must uncover whether this was an accident, or foul play. Warrick and Catherine try to find the killer of a 13 year old girl.

A woman is found dead in a hotel suite with symptoms of the ebola virus. Another woman is found dead with similar symptoms. Catherine and Nick investigate. Sara and Greg with help from Grissom try to determine how a the owner of a home was killed. His home was tented for infestation.

Grissom and Sara investigate the murder of a woman after a swap party. The married couples in the neighborhood meet and switch partners. With the help of a crime scene cleaner, Nick and Warrick find there was more to their crime scene than they first thought. Catherine wants a promotion to day shift supervisor.

A serial killer strikes again, and the CSI team tries new technology using evidence from a prior killing. They find a fingerprint belonging to Jesse Acheson, who becomes the prime suspect. A boy confesses to the killing of his brother, but evidence suggests that he may not have committed the crime.

A 28 year-old single mother is found dead. Initially, it's believed to be a suicide, but Catherine determines she was murdered. Also, Ecklie summons Grissom to refute the testimony of an entomologist in a murder trial.