外国学生宿舍谋杀案 (1955)

Hickory Dickory Dock is a work of detective fiction by the English writer Agatha Christie and first published in the UK by the Collins Crime Club on 31 October 1955 and in the US by Dodd, Mead and Company in November of the same year under the title of Hickory Dickory Death. The UK edition retailed at ten shillings and sixpence (10/6) and the US edition at $3.00. It features her Belgian detective Hercule Poirot. The novel is notable for featuring Poirot's efficient secretary, Miss Felicity Lemon, who had previously appeared only in the Poirot short stories.

This novel is set at a student hostel on Hickory Road, where Miss Lemon's sister Mrs Hubbard is the warden. Poirot attempts to discover the reason for a sudden spate of petty thefts and vandalism, as he suspects there is a darker aspect to the happenings at Hickory Road; these suspicions are confirmed when three people are murdered.

Plot summary

An outbreak of apparent kleptomania at Mrs Nicoletis' student hostel arouses Hercule Poirot's interest when he sees the bizarre list of stolen or vandalized items; a shoe, a stethoscope, a bracelet, a powder compact, a cookbook, some lightbulbs, some old flannel trousers, a box of chocolates, a rucksack, a silk scarf, some boracic powder, some green ink, and a diamond ring (later found in a bowl of soup). He congratulates the warden, Mrs Hubbard, on a 'unique and beautiful problem'.

When Poirot meets with the students and threatens to call in the police, Celia Austin quickly admits she is the primary thief. She denies, however, the following: stealing Nigel Chapman's green ink and using it to deface Elizabeth Johnston's study notes; taking Len Bateson's stethoscope, Chandra Lal's boracic powder, and the hallway light bulbs; and cutting up and concealing Len's rucksack. She committed the lesser crimes to attract the attention of Colin McNabb, a psychology student. This ploy succeeds - McNabb proposes marriage to Celia, who makes restitution for her crimes and hints that she knows who committed the others. Celia is discovered dead the following morning from an overdose of morphine tartrate; though the scene is staged as a suicide, investigators quickly rule it a homicide.

Inspector Sharpe interviews the inhabitants of the hostel. Nigel Chapman admits that he acquired the morphine tartrate as part of a bet to steal three deadly poisons without being caught (the other two being digitalin and hyoscine hydrobromide); he is also the one who stole Len's stethoscope, to disguise himself as a doctor and gain access to a hospital dispensary. He claims all the poisons were either burned or flushed down the toilet, but it is just possible someone managed to extract some morphine before this was done. Poirot turns his attention to the reappearance of the diamond ring, and confronts Valerie Hobhouse, in whose soup the ring was found. Valerie admits that she is the one who suggested the scheme of the thefts to Celia; however, Celia was only supposed to steal or destroy worthless items. Realizing Celia had accidentally stolen something valuable, Valerie took the ring from Celia, secretly swapped the diamond for a zircon to pay off some gambling debts, and staged the return of the ring.

Mrs Nicoletis begins behaving very nervously, and someone poisons her brandy to keep her quiet. Poirot focuses his attention now on the cutting up of the rucksack. By careful study of the rucksack's design, he identifies an unusual corrugated base, and suggests to the police that the rucksack is part of an international smuggling operation. The rucksacks were sold to innocent students, and then used to transport drugs and gems. Mrs Nicoletis had been bankrolling the organisation, but was not the brain behind it.

Patricia Lane comes to Nigel and admits that she took the morphine from the bottle in his drawer, and substituted bicarbonate of soda for it. Now the bicarbonate bottle with the morphine has been stolen from her own room. She also mentions that she intends to write to Nigel's dying father to reconcile the two, but Nigel tries to dissuade her, claiming that he has legally changed his last name and estranged himself from his father because his father secretly poisoned his mother with Medinal. Nigel goes to Inspector Sharpe and tells him about the missing morphine, but while he is there, Patricia telephones to say that she has discovered something further. When Sharpe and Nigel return to the hostel, they find Patricia has been bludgeoned to death.

West African student Akibombo reveals that he had taken Patricia's bicarbonate bottle to ease a stomach complaint; when he took a teaspoonful of the contents, however, he became very ill and later discovered that the white powder was in fact boracic powder. Therefore, by the time Patricia had substituted the bicarbonate, the morphine had already been substituted for Chandra Lal's stolen boracic powder. Poirot begins to suspect Valerie Hobhouse's real reason for convincing Celia to steal things is that she is in on the smuggling, and wished the destruction of the rucksack to be thought one of a series of unimportant crimes. A police raid on a dress shop that Valerie works for proves Poirot is right.