The first in a new series of crime mysteries set in Cambridge in the Second World War. Eden Brooke, once of Michaelhouse College, is a veteran of the Great War, and now a detectve inspector on the 'Borough' - one of the smallest police forces in the country, charged with keeping the peace in the university town's medieval centre. It is the opening weeks of the war and first complete Black Out - dubbed The Great Darkness - provides a platoon of soldiers with the cover they need to dig pits on St John's Wilderness. What lies beneath? The answer could affect the outcome of the war itself.