Late in the evening, an elderly history professor is killed near the city square. The investigation learned only one thing: a moment before his death, the scientist tried to throw away into the bushes a bunch of keys with a pendant made in the shape of the heraldic “Crampone cross.” There was an absurd impression that the professor was concerned that this pendant would lead investigators to the solution to his tragic death. The professor's student, a young scientist-historian Vlad, tries to find the killer on his own and heads to the Eternal City. He was not mistaken - the killer is hiding right there, in the dense shadow of the ancient Roman streets, where, under the shadow of history, people and non-humans came together in mortal combat...