Tommaso Santini, together with the Sanctum Consilium Solutionum, is called again to solve a mysterious case that undermines the roots of the Church. Thirty-three years earlier, the semen of a boy, possessed by the Devil, was taken to fertilize a young woman. Nine months later, Belial Bompiani was born. A satanic sect made Belial the new Antichrist, thanks to a profane text called: The Dark Bible. A nefarious prophecy will make Belial, at the beginning of his thirty-third year of life, a destructive instrument that will want to mortally strike the Church by making use of that execrable text.
Once again, the Solver will find himself facing an unspeakable enemy. He and his team are given the task of finding who may be the man who embodies the son of Satan and to kill him before he can make it to his thirty-third year of life.