The Submarine Plans by Agatha Christie. Short summary

5 seconds

Poirot is called urgently in the middle of the night to help find the secret blueprints for a new submarine that were stolen from Lord Elloway’s house.

1 minute

A story in the «Hercule Poirot» series. During a party at the estate of Lord Elloway, head of the Ministry of Defence, some very important documents disappear — the secret drawings of the new submarine type «Z». Poirot is urgently summoned to look for them.

Poirot proceeds to interview witnesses. The landlord believes that someone has been in the house, for Mrs Conroy, the maid, claims to have seen a ghost. Poirot examines the grass outside the window of the study and finds no traces, which means that someone in the house has committed the theft. At this point, Lady Werdale appears and asks Poirot if the case can be settled if the plans are returned within ten minutes. Poirot lays out the proposal to Lord Elloway, without naming names, and leaves.

Poirot assumes that the kidnapper is the owner of the house himself. Agents of another state blackmailed the engineer into giving them the plans for a new submarine. But Elloway made small changes in the design of the submarine, due to which the model lost its functionality.