The Malet Conspiracy closely parallels the 1944 Stauffenberg Plot - also essentially the work of one man. That too, despite the failure of the bomb, seemed to be going smoothly, until Dr Goebbels, knowing that Hitler was alive, talked the officer sent to arrest him into allowing a telephone call to the Fuhrer. 
A fascinating book, about an historical event which would be utterly incredible as fiction, yet which really happened. If you are remotely interested in the period, grab it.