The CSIs investigate the mysterious death of a competitive eating contestant, and Chavez partners with Allie to prove where the mysterious silver ink notes have been coming from.

Medical examiner Sonya's life is in jeopardy when she is exposed to a mysterious poison as the CSI team races to find the antidote and the silver ink murderer who appears to be targeting the Crime Lab. Max's ex-husband, Daniel, returns to make sure that she and their son are safe.