It was not until we were in the train, speeding towards Paris that he admitted that he was secretly glad of my decision.

“For you have a part to play, Hastings. An important part! Without you, I might well fail. Nevertheless, I felt that it was my duty to urge you to remain behind.”

“There is danger, then?”

“ Mon ami , where there is the Big Four there is always danger.”

On arrival in Paris, we drove across to the Gare de l’Est , and Poirot at last announced our destination. We were bound for Bolzano and Italian Tyrol.

During Harvey’s absence from our carriage I took the opportunity of asking Poirot why he had said that the discovery of the rendezvous was my work.