Young Poisoner's Handbook

The film's portrayal of Graham Young is not wholly true to life, and thus, the film is not truly biographical. Nonetheless, the main truths about him are conveyed. He was a poisoner, a murderer, a genius and a thoroughly amoral man.

Early scenes show Young as a child preoccupied with the macabre. In his teen years, he actually poisons a schoolmate — sickening him rather than killing him — in order to date a girl his schoolmate was seeing. His conversation with his date involved vivid, graphic descriptions of deadly car accidents.

He also reads a comic book account of an event in which the Dutch Resistance killed a whole German army camp in the occupied Netherlands during the Second World War by poisoning their water supply with thallium.

Graham Young is arrested at the age of 14 outside his home in Neasden after having killed his stepmother and having tried to do the same to his father by lacing their food or medicine with thallium. During the struggle with police Young abuses the policemen because he drops his "Exit Dose" of thallium which he intended to use to commit suicide should he be caught. He is imprisoned for nine years in an institution for the criminally insane, during which time a psychiatrist works with him in the hopes of rehabilitating him.

Graham's dishonesty becomes evident to the doctor, who can see that Graham is trying to deceive him. Graham apparently has no dreams to share with the psychiatrist so he "borrows" a fellow prisoner's dreams. This source is shut off to him, however, once the fellow prisoner commits suicide. Despite the initial evidence of deceptiveness on Graham's part, the doctor eventually gets him released.

Graham then goes to work in a camera factory and is shown the secret ingredient used in the company's shutter system — thallium. It is not long before Graham has reverted to his old behaviour and is poisoning people. He kills two of his workmates by poisoning their tea with thallium stolen from the laboratory, and he sickens many others. For months, the source of the "bug" afflicting the workers at the factory remains a mystery until one unforeseen event leads to Graham's being found out. As a hygiene measure, all the personalized teacups are replaced with uniform ones, leaving Graham unable to poison people selectively. His efforts to memorize which cup is going to which person give him away, and his workmates finally realize what is going on.

Graham is arrested soon afterwards, and he is later sentenced to a lengthy prison term, this time in an ordinary prison. He commits suicide by poisoning there, unlike the real Graham Young, who died of a heart attack. The film insinuates that Graham's ambition in life was to create a diamond using his poisons and chemistry knowledge, in reality his ambition was to become an infamous poisoner which he achieved.