L'Éclat d'obus

Leblanc wrote this 1916 novel in the middle of the First World War, and the war shows up in every chapter. The original French title L'Éclat d'Obus translates roughly as The Shell-Shard, though English editions have also used The Frontier. The book is unusual in the Lupin catalogue. Lupin himself appears only briefly, and the focus stays mostly on a young French nobleman caught between his family heritage and the German invasion of his border region.

There is espionage, a hidden chateau, a buried secret about a coded message left by a previous generation, and the kind of patriotic flag-waving that was very much in fashion in 1916 French publishing. Modern readers may find the wartime sentiment dated, and that is fair. As a historical document about how popular French fiction responded to the war in real time, it is genuinely interesting. As a Lupin novel it is one of the odd ones, and longtime fans tend to either love it as a side trip or wave it off entirely.