This is the story of how one young man's ruthless attempt to poison his family in order to gain his inheritance led to the birth of modern toxicology.In the 19th century criminal poisoning with arsenic was frighteningly easy. For a few pence and with few questions asked, it was possible to buy enough poison to kill off an entire family, hence arsenic's popular name: The Inheritor's Powder. Yet if poisoning was easy, it was a notoriously difficult crime to prove. The popular press led to the nation becoming transfixed by the idea that danger lurked in every cup and on every plate. "The fell spirit of the Borgias" was "stalking through English society" wrote one commentator. Thus, armed with a coffee pot and some 'rat poison' young John Bodle saw his opportunity. The case became a cause celebre, and drew the attention of the experts.

Michael Faraday asked a young chemist, James Marsh, to develop a failsafe test, ushering in an age of medical experts who kept the gallows busy, although questions then began to be asked about just how failsafe this new test actually was.