The Best Episodes Written By Siena Butterfield

After an explosion in a bio lab, the CSI team races to determine which nerve agent left one of their own unconscious, while the others explore a dangerous underground tunnel to find another CSI who got kidnapped during the blast.

With Tyler on the loose, Wednesday readies for a risky Día de los Muertos showdown. Slurp's growing hunger poses problems for Pugsley.

Catherine’s frustration intensifies when a lead suspect in Grace’s disappearance is found murdered. The team exhausts all their skills to figure out who killed the suspect, and if his death will lead them to Grace.