The novel covers a significant period in the life of Queen Isabella of Castile (Catholic) and her husband King Ferdinand of Aragon. Events unfold against the backdrop of the rise of the Spanish Inquisition. Isabella, with the help of the Grand Inquisitor Thomas Torquemada and his follower Jimenez de Cisneros, tries to convert the “infidels” to Christianity and at the same time wages war with the Moors. And as if in revenge, misfortunes befall the prosperous royal house: hereditary diseases, madness, the death of children, and most importantly, the only heir. The enemies of Isabella are not slow to take advantage of the situation, who want to make Joanna Beltronea, the daughter of the former queen who is in captivity, queen of Castile. Ferdinand of Aragon tries to save the situation and decides to place his daughter Isabella on the throne. But will the independent Aragonese allow a woman to ascend the throne?..