In the twelfth century AD, Venice is little more than an agglomeration of small islands snatched from the muddy tides. The magnificent city-lagoon of Venice, the rich and powerful Serene Republic, is yet to be born. Here, in this northern backwater, a group of artisans have proven themselves to be unrivalled in an art form that produces works of such astounding beauty that many consider it mystical in nature and think its practitioners possessed of otherworldly gifts: glassmaking. Presciently aware of the power they wield and the role they will play in the Venice of the future, the Venetian glassmakers inhabit a world of esoteric practices and secret knowledge that they protect at all costs.
Into this world steps Edgardo D'Arduino, a cleric and a professional copyist. Edgardo's eyesight has begun to waver-a curse for a man who makes his living copying sacred texts. But he has heard stories, perhaps legends, that in Venice, city of glassmakers, there exists a stone, the "lapides ad legendum," that can restore one's sight. However, finding men who have knowledge of this wondrous stone proves almost impossible. After much searching, Edgardo meets a mysterious man who offers him a deal: he will lead him to the makers of the lapides ad legendum in exchange for Edgardo's stealing a secret Arabic scientific text that is kept in the abbey where Edgardo lodges. When a series of horrific crimes shakes the cloistered world of the glassmakers, Edgardo realizes that there is much more at stake that his faltering eyesight.
