Dennis Wheatley's strange conflict is a book in the Duc de Richleau series, the series which started in the 1930's has now moved into the realm of the second world war and is set in 1940.
The book looks at strange successes of the Nazi U-boats for their ability to shadow Allie convoys sending the shipping to the bottom of the Atlantic. This attack is causing Britain tremendous pain and if continues will cause Britain to sue for peace and allow the Nazi's free range over Western Europe.
Enter the duc de Richleau, he's the character we've met in the Forbidden territory and is an expert on black magic, he is a French aristocrat in his fifties, he is intelligent, good looking and always feels like he should be played by Christopher Lee when I first read the book in the mid eighties. He's urbane, slightly arrogant but generally a decent man, he lives in London though is a french Duc, he has acquired a small group of younger fitter helpers and they set out to solve the conumdrum.
Quickly they find out that the Nazi's are using black magic to aide there war effort, they find it out when a Navy general opens some orders and a purple cloaked figure appears behind him. Suddenly the hunt is on for the Nazi magician.
This adventure is more spectral than te previous novels it tends to focus on the astral realms and the battle between good and evil, the novel tries to tie this endless struggle to the second world war where the struggles are becoming focused on the struggle between evil Nazi Germany and the good pure British empire. Wheatley was at this time a member of the planning staff at the war office so the book is hugely biased away from the Germans and towards those fine fighting men from the British Expedition Force, however, if we take that with a grain of salt this novel is a decent one.
The action is on a more cerebral level than a classic war adventure, the Duc fights the Nazi's on a more intellectual level than a physical one.
Of course the Duc wins through and the Nazi threat is beaten, but the book does have a darker side, anyone fighting the dark magic will inevitable become tainted by their magic so the book ends with the Duc struggling with some of the actions he had to perform to succeed.