Allingham offers up your classic 1933 puzzle mystery in which detective Albert Campion and his odd group of compatriots work to secure the newly strategic port of Averna for Britain by solving a three-part puzzle before the diabolical Savarnake, a villain of unknown nationality. The puzzle solving takes place in a small Suffolk village where Amanda Pontisbright--eventually to be Amanda Campion--and her family seem to be the heirs to Averna, but have yet to prove title. The book is rife with themes suggested by the events of 1933: Campion appears to be working for the government somehow, and the urgency to secure Averna port and oil resources reflects the coming war with Germany. But mostly it's a fun puzzle mystery with mistaken identities, a spooky mill, and steampunk technologies.