Based on the true story of London teenager Graham (O'Conor), who's obsessed with chemistry and at odds with his stepmother. So, he poisons her chocolates and she dies. Sent to Broadmoor prison for the criminally insane, Graham comes under the care of Dr. Ziegler (Sher), who, eight years later, recommends Graham for parole. Now working in a photographic lab, Graham decides to experiment with doctoring his co-workers tea--which results in eight more deaths before Graham is caught. Locked up again, Graham spends his time writing a poisoner's handbook for Dr. Ziegler. Be warned that the sufferings of the poisoned victims are gruesome.