Florence, June 1300. The body of an artist, his face covered in quicklime, is discovered next to the mosaic he had almost completed. Dante Alighieri, the newly appointed prior of the city of Florence who will one day author the Inferno, is on the case in his first official investigation. Obscure clues lead him on a trail full of intrigue. What was the secret that might have been revealed had the artist lived to complete his work? Was it an alchemist's formula to transform lead into gold? Or the identity of an heiress to the Swabian throne, whose rumored arrival could upset the political aspirations of Pope Boniface, Dante's nemesis? Soon Dante comes to know the learned men who make up the so-called Third Heaven. Scholars of various disciplines, they appear to be increasingly linked to the mosaicist's murder and the corrupt underbelly of the respected, cultured city of Florence.