Black Coffee, (Hercule Poirot 7.5), Agatha Christie (stage play), Charles Osborne (novelization). William Morrow (ISBN: 9780061739323) 2004 (Stage play, 1930; Novelization, 1998).

Summary: Poirot is too late to help Sir Claud, who has been fatally poisoned and his secret formula stolen by someone in his household.

I like my coffee black. But I think I would pass were I visiting the home of Sir Claud Amory.

Black Coffee was actually Agatha Christie’s first stage play, overshadowed by the widely staged The Mousetrap. The play was moderately successful, playing in several theatres from December 1930 through June 1931. It also appeared as a film version in 1931. Among those over the years who played the suspicious Italian Dr. Carelli was Charles Osborne. Forty years later he approached the Christie Estate with a proposal to novelize the stage play. This book, published in 1998, was the result.

Sir Claud Amory reaches out to Poirot for help. He is working on an atomic formula that would create a powerful weapon. He suspects someone in his house wants to steal it. Before Poirot arrives, he finds the formula missing. He stages an elaborate effort to recover the formula at a dinner party with members of the household and guests. He locks them into the library. After coffee is served, he tells them the lights will be turned off, the thief can return the formula, and life will go on. Then he drinks his coffee, the lights go out and come on just as Poirot arrives.

An envelope is by his side. But Sir Claud is very dead. And the envelope is empty.

The authorities ask the guest to remain. Beside servants, there is Sir Claud’s sister Caroline, his spirited niece Barbara, his son Richard, who is in financial straits, Richard’s wife, Lucia, who he recently married in Italy, Sir Claud’s efficient secretary Edward Raynor, and Dr. Carelli, ostensibly Lucia’s friend. Instead, he is blackmailing her, threatening to reveal her past.

Poirot is accompanied by Captain Hastings. Soon they learn that someone used hyoscine to poison Sir Claud’s coffee, explaining the bitterness he complained of when drinking it. Suspicion focuses on Lucia, who had been seen taking some tablets from a medicine box they had been looking at earlier in the evening. She had served the coffee. And there was her past. She was the daughter Selma Goetz, an international spy. She had tried to keep this secret from the family but Dr. Carelli knew and Sir Claud had received a cryptic warning about her as well.

Poirot knows she isn’t the murderer, nor her husband, who confesses to protect her. Eventually he sets a trap to catch the thief and murderer. But the murderer turns the tables, using the same poison in Poirot’s drink.

This is a short piece, and while a bit formulaic, makes for a diverting read. It makes sense that this was a stage play. All the action takes place in the library. The character of Poirot is consistent with the other novels. Although the stage play preceded the nuclear age, the story also raises the question about the morality of such super weapons. Although this is not up to the standard of The Murder of Roger Ackroyd and And Then There Were None, any Christie and Poirot lovers will want to read this, particularly to learn the plot of Christie’s first stage play.