"I should imagine this was murder, too, because it would be very difficult to build yourself into a heap of sandbags and then die..." In the blackout conditions of a wintry London night, amateur sleuth Agnes Kinghof and a young air-raid warden have stumbled upon a corpse stowed in the walls of their street's bomb shelter. As the police begin their investigation, the night is interrupted once again when Agnes' upstairs neighbour,...