In the summer of 1962, fourteen-year-old Graham Young stood in the Old Bailey dock charged with poisoning family members and a schoolfriend by methodically lacing their food and drink with such substances as thallium and antimony. Diagnosed with 'a psychopathic disorder', he was detained under the Mental Health Act and committed to Broadmoor, the youngest patient there since 1885. Nine years later, Graham was released, believed to be no longer a danger to others. He found employment at Hadlands, a photographic supplies firm. In his role as an assistant storekeeper, Graham's duties included collecting and serving his colleagues' morning and afternoon tea. Very soon, members of staff began falling ill, experiencing debilitating pain - and dying...