Josh and Chuck recount the 1982 Chicago-area Tylenol murders, in which seven people died after ingesting cyanide-laced extra-strength Tylenol capsules. They walk through the broader context of a tense year in America, the detailed timeline of each victim's death, how investigators discovered cyanide in the capsules, and the ensuing public panic and copycat tampering incidents. The episode closes with the formation of a multi-agency task force and the leading "mad poisoner" theory that the tampering occurred at or around retail stores rather than in the factory.