The first Miss Marple mystery, one which tests all her powers of observation and deduction. "Anyone who murdered Colonel Protheroe," declared the parson, brandishing a carving knife above a joint of roast beef, "would be doing the world at large a favor!" It was a careless remark for a man of the cloth. And one which was to come back and haunt the clergyman just a few hours later - when the Colonel is found shot dead in the clergyman's study. But...

Tommy and Tuppence Beresford, two unlikely spies, help to defend their country by trying to rout out two highly placed Fifth Columnists. When Tommy is asked by the British Intelligence Service to go and stay at the Sans Souci guest house he is astonished to see Tuppence there. The mission: to identify which of the other guests is N and which is M. - Publisher.