1741. Antonio Vivaldi sends his friend Tommaso Bellini a strange message in the form of an encrypted score, in which he tells of an astonishing discovery he has made. It turns out to be so dangerous for the future of all humankind that Bellini hides Vivaldi’s secret even from the members of the Fraternitas Caritatis brotherhood to which they both belong. Soon both Vivaldi and Bellini die, and the score—and the key to it—disappear as if without a trace. Only two and a half centuries later, thanks to a chance find, does the secret of the famous musician finally come to light. However, it still contains such a threat that it is preferred to be hidden away forever…