Once, in a gods-forsaken hellhole called Koom Valley, trolls and dwarfs met in bloody combat. Centuries later, each species still views the other with simmering animosity. Lately, the influential dwarf, Grag Hamcrusher, has been fomenting unrest among Ankh-Morpork's more diminutive citizens-a volatile situation made far worse when the pint-size provocateur is discovered bashed to death . . . with a troll club lying conveniently nearby. Commander...