This was the only other Tommy & Tuppence novel available from my high school library, and in those pre-internet days I never became aware that Christie had actually written a few others featuring one of my favorite detecting duos. In this book, Tommy & Tuppence have long since retired from spy-catching to a house in the English countryside. Naturally, they stumble into a mystery, and haven't lost their energy or sense of adventure for now being in their 70s. Altogether a fun read.