Paul Vivanti is a British evil genius.
It is important to state up front that each of those three words of description are very important to understanding the series of adventures that the British Secret Service as a whole and several agents of it specifically will undertake in order to stop the man from carrying out his ultimate plan - the destruction of Great Britain.
Once the most celebrated nerve-specialist in Harley Street [London}, lately the controller of a world-wide gang of criminals.
He was one of the pioneers in the new medical treatment known as 'organotherapy' having worked with a famous researcher named Meyerbach in Vienna many years before. He was highly regarded in the medical and scientific communities and was well known in the business world as well. That was all before it was known what kind of man he really was.
His descriptions are many and all of them give the same sort of eerie feeling about him. "[Vivanti's] face was suddenly transfigured. Evil it had looked before, but now it became devilish." "[He had] unnaturally long fingers frequently said to be about to "twine around" throats of people he became upset with."
Also, he possessed a "voice that held a whip-lash authority" with a "tone [that] was sharp, business-like, extraordinarily compelling". "Of slight - almost childish - build, his huge head dominated his seemingly frail body. It was remarkable head, bald in front and protruding in a bulge behind - the head of a great genius - or of a great criminal". "His face was pale, and this pallor was accentuated by carmine lips - lips so read that they might have been painted. From out the death-like pallor of his face, huge deep-set eyes glowed with an unnatural light. A man driven by a devil, some would have said. An evil in human guise."
Vivanti's membership in this compendium comes because his efforts to first dominate the country and then, when stymied by agents of British Intelligence, destroy it. His will not be a single attempt - his genius would not only get him close to success but also make sure that when he is stopped, he had an escape route that allowed him to get away to try again. And again. And again.
His hatred and his avarice will be even take him, during the Second World War, to Germany and a meeting with Adolph Hitler to help bring down Britain, twenty years after he first started his reign of terror.
Combatting him will be operatives, sometimes amateurs and other times experienced professionals, under the direction of Sir Herbert Mandeville, the Secretary of the National Security Department.