"Sir Claud Amory has discovered the formula for a new powerful explosive, which is stolen by one of the large household of relatives and friends. Locking everyone in the library, Sir Claud switches off the lights to allow the thief to replace the formula on the table, no questions asked. When the lights come on, he is dead, and Hercule Poirot - joined by old favourites Hastings and Inspector Japp - try to unravel a traditional Christie spy-cum-murder thriller in which we learn of family feuds, old flames and suspicious foreigners, which is all resolved in typically unexpected fashion. Agatha Christie's first play, Black Coffee was first performed in 1930. It was made into a now rarely-seen film the following year. Now Charles Osborne, author of The Life and Crimes of Agatha Christie, has written a novel based on the play."--Provided by publisher.