Professor Toller has created a devastating weapon that could change the world as we know it. The threat is imminent as the Professor and his formula are kidnapped and it is left to the head of Department Z, Gordon Craigie to save the day.

Department Z is a small and little-known section of the Intelligence Service. Among the other branches its work was legendary. There are agents of the Department in most of the world’s capitals and in many smaller cities, and many strange matters passed through its hands. Or, more accurately, the hands of Gordon Craigie and Bill Loftus.

Craigie must take enormous risks as both Washington and Moscow begin to suspect Britain of seeking out such a destructive weapon. His investigation leads him to an English seaside resort where Craigie must track down the men that have taken the professor whilst evading the master conspirator who is out to get him. When the conspirator goes after the Prime Minister, Craigie is in real trouble.

The Peril Ahead is the 22nd novel in the Department Z series, and was originally published in 1946.