First published in 1941, this crime story finds Tommy and Tuppence Beresford in a prim seaside boarding house, frequented by genteel old ladies and retired army... » 

First published in 1941, this crime story finds Tommy and Tuppence Beresford in a prim seaside boarding house, frequented by genteel old ladies and retired army officers. But one of them is a spy, leader of the fifth column of highly placed traitors. «