Umberto is a Milanese physician now close to retirement. By pure curiosity he investigates the origin of his surname and finds out an ancient noble Tuscan origin. A Ghibelline ancestor had taken refuge in 1285 in a Sienese castle and the bishop of Arezzo, Guglielmo of the Ubertini, stirred a rebellion against the city of Siena, which ended months later with a massacre. The protagonist, fascinated by the beauty of the place, decides to buy a house near the castle, now abandoned and inaccessible for years; he leaves Milan to move and spend old age. During the renovations, he finds an ancient Florentine coin, a copper florin, also known as black florin, and Cesira, a clairvoyant, perceives that the coin belonged to a very important person: Dante Alighieri, and was lost in dramatic circumstances. The novel tells the story of Riccardo, a Florentine man who flanked the young Dante Alighieri during the terrible siege of the castle. The story of young Riccardo in the thirteenth century intersects with that of Umberto to our day and, to both, the events that take place in that castle will change their life forever. Umberto, like Riccardo centuries before, will find love in that place. Two protagonists of different ages, in parallel with each other, challenge the unknown by discovering new and unexpected passions. An adventurous history of men, weapons and love that intertwines between the Middle Ages and our days.