Black brillion.

Boro Harkless has devoted his life to the service of the Archonite Bureau of Security, the force tasked with keeping the peace among and within the city-states of Old Earth. He comes to the city of Sherit seeking the criminal, Luff Imbry. Luff Imbry has devoted his young life to the enjoyment of wealth. A gourmet, a charmer, and an ever-so-stylish fop, he has come to Sherit to pursue a new fortune. Not, mind you, his own, for Luff is also a mountebank, swindler, and forger of the first water. Yoked together by circumstance, they form an uneasy truce and discover a common goal: capturing the grandest con-man of them all, Horselan Gebbling. Gebbling, who made off with Imbry's previous fortune, is posing as Father Olwyn, Sacredotal Eminence of the Assembly of Tangible Unity, and now claims to cure the invariably fatal ailment known as the lassitude with Black Brillion. But the gemstone is a myth, as our heroes know.