Cambridge, 1939. The opening weeks of the Second World War, and the first blackout – The Great Darkness – covers southern England, enveloping the city. Detective Inspector Eden Brooke, a wounded hero of the Great War, takes his nightly dip in the cool waters of the Cam. Daylight reveals a corpse on the riverside, the body torn apart by some unspeakable force. Brooke investigates, calling on the ex...