The episode features the Season 6 Regular Cast alongside several notable guest performers: as Gil Grissom Marg Helgenberger as Catherine Willows Jeffrey Nordling as Mark Thayer (Guest Star) Kristin Bauer as Kenli Johnson (Guest Star) Jenny O'Hara as Sandra Walkey (Guest Star) Conor O'Farrell as Undersheriff Jeffrey McKeen
The episode follows two distinct narrative arcs that highlight different aspects of forensic science:
: Grissom discovers that Thayer sprayed his experimental subject with malathion, a pesticide that delayed the flies' development by four days. By proving this "clock tampering," Grissom gets Thayer arrested for perjury and obstruction of justice. Key Cast and Guest Stars
: The trail leads to Kenli Johnson, a woman whose mother, Sandra Walkey, ultimately confesses to the murder. Sandra killed Christina to ensure Kenli would gain custody of Joey, as Kenli was the biological mother who had lost her son in a previous custody battle.