Sue Zen Chew

When a lead suspect in Grace's disappearance case is found murdered, Catherine's frustration intensifies. The team attempt to figure out who killed the suspect and if his death will lead them to Grace.

CSI investigator Catherine Willows persuades Maxine Roby to let her rejoin the team. A dominatrix is found murdered, and Allie returns from Los Angeles to help understand the complicated DNA evidence at the crime scene.

After all the guests attending an upscale science department fundraiser at a local university fall ill, the team gear up to investigate. Meanwhile, Catherine seeks help from Grace's roommate to help her find clues after Grace disappears.