Bob Kerr had every reason in the world not to want a visitor that afternoon.

Looking forward to a relaxing afternoon away from the trials of Department Z, Bob Kerr eagerly awaits the arrival of fellow agent Lois Dacre. He is temporarilty amused by the sight of a passer-by oddly dressed in an enormous fur coat on an exceptionally warm day. Disrupted from his reverie by a call from Agent Craigie, Kerr is alerted to new developments in the principality of Vallena. Kerr cuts the call short to answer a knock at his door.

Suspiciously, the visitor is the man in the fur coat. Come from Vallena.

The information the man relays to Kerr is life-threatening. The visitor has a hit out on his own life and Kerr is next on the list.

As the number of assassinations in Vallena mounts, British officials are put in the line of fire. Agent Kerr and Department Z must work swiftly must work swiftly and tirelessly in order to topple the criminal organisation before another life is lost.

Menace is the 11th book in the Department Z series, and was originally published in 1938.