The first Tommy and Tuppence mystery finds the charming pair meeting up after the first world war, having an adventure, falling in love, and starting their life together. It’s a jaunty novel in a lot of ways that springs from the kind of hope that peppered the 1920s for a lot of people. This novel takes place in 1940 (and was published in 1941) and the shadow of a Nazi-occupied Europe and the very possible fall of Great Britain to the Nazis has added a bleakness to the tone of mysteries. In addition, Tommy and Tuppence are 20 years older, parents, and now in their mid-40s are finding that the war effort needs and (worse) wants less from them now. But because of the secretive nature of their previous work, they are approached by the war office to help root out homeland spies, particularly in a single town, who are planning some kind of invasion or act of sabotage. Going by the moniker of either N or M, these moles pose a huge risk.
This is a really solid spy novel and a good mystery too, as it is both at once. The anxieties about WWII and the fear of the total loss of their country are real and terrifying, and the anxieties about aging add a level of sadness and charm too. Because it was written in the midst of the war, perhaps a quaint mystery feels less than ideal (although she wrote plenty of those too) but there’s kind of patriotic zeal to this book that is tinged with fear and sadness in earnest ways.