Mr. J. G. Reeder, employed by the Department of Public Prosecutions, has developed a reputation for solving difficult criminal cases using his unique understanding of human nature, which he calls his “criminal mind.” After a notorious bank robber and murderer escapes from prison, Mr. Reeder must match wits with Crazy John Flack, the “cleverest crook in the world,” who previously vowed to kill the famous detective in revenge for his imprisonment.

Reeder’s love interest Margaret Belman receives a lucrative job offer at an exclusive country hotel located at the famous Larmes Keep. As Reeder pursues several leads on Flack’s whereabouts, he discovers that Margaret’s new position is part of Flack’s plan for revenge. When Reeder rushes to Larmes Keep in an effort to keep Margaret safe, he’s surprised to find that Crazy John is one step ahead of him.

Published in 1927, Terror Keep was the third book to feature Edgar Wallace’s answer to Sherlock Holmes .