A French refugee is washed up on the English coast. Feverish, delirious, he babbles incoherently to the men who find him. A single phrase, repeated: ‘Lotfus, spell it backwards.’

This discovery sparks an explosive reaction at throughout Department Z, whose agents- including recent amputee Bill Loftus himself- are fighting a desperate battle to uncover a Nazi scheme that threatens the very heart of British Defence.

After startling revelations of a conspiracy theory, a kidnapping plot and a dangerous weapon Department Z find themselves in over their heads.

The Day of Disaster is the 18th book in the Department Z series, and was originally published in 1942.