With their respected colleague Josh Folsom under arrest for the death of Kahn Schefter - the man responsible for killing Folsom's mother - the CSI team combs through every crumb of forensic evidence to determine his innocence or guilt.

With a new piece of evidence at play, Catherine Willows reopens an investigation from her past that never got solved after a violent attack left her hospitalized. Internal affairs begins questioning Folsom.

The CSI team is called to investigate when the bodies of Frank Sinatra and Joey Bishop impersonators are discovered behind the drywall of a home construction project. Also, Folsom must face the review board about the future of his career.

The whole team comes together to investigate an apparent occult killing.

The CSI's poisoning investigation is hinder by a contaminated scene, and not being able to find the source of the contamination.

The CSIs investigate when the owner of a gym is found dead in the sauna.

The CSI team investigates when a plastinated nervous system is found displayed in a car dealership. Meanwhile Chavez and Max search for Valerie.

The CSI team probes an antique shop owner's gunshot death lacking a crucial clue - the bullet. Meanwhile, Max gains ground in the ongoing robotics factory case involving Ocho.

Max takes the opportunity to covertly gather evidence from the robotics factory, but discovers espionage isn't one of her talents.