From the Module description:
The Emissary of Phlan, an Half-Elven adventurer by the name of Leaffern Gallianius, has stopped by the town of Silver after a lengthy mission to the High Grand Duchy of Elkhorn. On the agenda of his discussions were the cessation of hostilities between Phlan and Elkhorn, trade agreements between the two polities and the protection of the Elkhorn and Phlan silver caravans from the mines each of them are exploiting in the Unnamed Massif to the North.
As an indication of goodwill and faith in the contract, Bark Gallianius, Leaffern's brother, remained behind in Elkhorn as a hostage to the contract. Elkhorn reciprocated and sent The Dukes youngest son, Karl Bjornsson with Leaffern to spend the next two years in Phlan.
AD&D 1st EDITION for Four players for 14th -19th Level Characters.