Hastings, Poirot and Japp go to the movies, seeing gangster films. Poirot is not impressed by solving crime US style with guns.
It just so happens a FBI detective has taken over Inspector Japp's office at Scotland Yard as he is on the trail of some stolen submarine plans from the US Navy. They have come across a man outside the Italian Embassy in London who appears to be familiar to Poirot.
The crux of the matter is that a young couple, the Robinsons have managed to rent a cheap flat that has been available to rent for some weeks which they brag about in a dinner party that Poirot has attended. Poirot thinks that the Robinsons are in danger.
This is an espionage tale but I did not think it hangs together well. A femme fatale who lured a young clerk in the navy and then double crossed the mafia.
Of course it was ironic to see Samantha Bond play Mrs Robinson who would go on to play Miss Moneypenny in the Pierce Brosnan Bond films. Also keep a look out for a scrubbed up Gordon Wharmby, better known as Wesley the car mechanic in The Last of the Summer Wine.