S7, E5: Student Nikolas Resche is killed by a poisoned dart while jogging near his elite boarding school. The investigation reveals a chilling plan, with several suspects capable of creating the deadly toxin derived from frog venom. As the detectives delve into the lives of his classmates and teachers, a web of secrets and scientific knowledge begins to emerge. Each clue draws the team closer to a meticulously planned murder rooted in jealousy, manipulation, and academic rivalry.