Fools' Gold (Order of Darkness #3)

Luca Vero and his friends are plunged into the heady whirlwind of Venice, the world's busiest marketplace, where everything and everyone is for sale. Their mission from the Pope is no protection: this city has its own laws. Meanwhile, the Lady Isolde is in more danger than ever and her feelings for Luca are becoming more intense. As the friends face the unknown dangers of magic and alchemy, the crimes and politics of the city may become the least of their worries. The powers they confront are not of this world.