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The Adventure of the Cheap Flat is a short story written by Agatha Christie. It was first published in The Sketch in May 1923 in the U.K. The story was published in the U.S. in The Blue Book Magazine in May 1924. In 1924, the story appeared as part of the anthology Poirot Investigates.


Hastings meets a couple at a party who have just rented a flat in a fashionable district for an implausibly cheap price. Poirot is intrigued and sets out to investigate.

Plot summary

(may contain spoilers - click on expand to read)

Hastings is at a friend's house with several other people when the talk turns to flats and houses. A young couple by the name of Robinson are there and she tells the party how they have just managed to obtain a flat at Montagu Mansions in Knightsbridge for the very low price of 80 pounds a year. Strangely, the flat had been on the market for a few months but had not been let out.

Poirot hears this and is intrigued and so decides to investigate. They go to Montagu Mansions. There the porter tells them that the Robinsons had been there for six months!

Poirot rents another flat in the building and, by use of the coal lift, manages to gain entry to the Robinson's flat and fixes the bolt of the door in order that he can enter at will later.

The next day, Poirot tells Hastings that Japp informed him that important naval plans were stolen from America. The key suspect was a junior government official named Luigi Valdarno. He was later found dead but he had been going out with a known international spy, Elsa Hardt. Hardt's description is a somewhat close match to that of Mrs Robinson and she was believed to have fled to England to try to sell the plans. Moreover, Poirot has learnt that a swarthy man has been asking about the Robinsons.

That night, Poirot and Hastings sneak into the Ronbinsons' flat by the coal lift and lie in wait. As anticipated, a man breaks in the front door. Hastings and Poirot apprehend him and bundle him in a taxi to a house at St John's Wood. That turns out to be where Elsa Hardt was hiding. Poirot had located it by having Elsa followed as she moved out of Montagu Mansions. Japp is waiting there with a U.S. Secret Service agent. The spies are arrested and the plans recovered.

Poirot explains that the swarthy man was probably from an Italian secret society like the Mafia or Camorra. He had tracked down Elsa Hardt to avenge the death of Luigi Valdarno, an Italian American and probably a fellow member of his order. When Elsa learnt that they were looking for her, she sublet her flat to another couple of the same name as a decoy.


Film, TV, or theatrical versions

Agatha Christie's Poirot

A television film with David Suchet as Poirot was produced as episode 7 of Series 2 of the ITV series Agatha Christie's Poirot, first broadcast on 18 February 1990. The adaptation is fairly faithful to the original story with embellishments.

Agatha Christie's Great Detectives Poirot and Marple

The novel was adapted as an anime film for television as episode 2 of the NHK anime series Agatha Christie's Great Detectives Poirot and Marple and broadcast 18 July 2004.

Publication history