July, 1700, Rome. Atto Melani – once a celebrated castrato soprano, now a spy in the service of King Louis XIV – mingles with other high-ranking guests at the villa of Cardinal Spada. Despite being there to celebrate a wedding, the main topic of conversation is the approaching demise of Charles II, King of Spain. Charles has no heir and Kaiser Leopold of Austria and King Louis are each demanding the throne, with the Vatican supposedly mediating. Keen to promote his master’s cause, Melani sets in motion a grandiose conspiracy that plunges him into a world of secret languages, religious sects, forged wills and, ultimately,war in Europe.