Commander Sam Vimes of the Ankh-Morpork City Watch will be damned if he lets anyone disturb his city's always tentative peace —and that includes a rabble-rousing dwarf from the sticks who's been stirring up trouble on the eve of the anniversary of one of Discworld's most infamous historical events.

Centuries earlier, in a hellhole called Koom Valley, trolls met dwarfs in bloody combat. Though nobody's quite sure why they fought or who actually won, each species still bears the cultural scars and views the other with simmering animosity. Lately, an influential dwarf, Grag Hamcrusher, has been fomenting unrest among Ankh-Morpork's more diminutive citizens. And it doesn't help matters when the pint-size provocateur is discovered beaten to death... with a troll club lying nearby.

Vimes knows the well-being of his city depends on his ability to solve the Hamcrusher homicide. But there's more than one corpse waiting for him in the vast mine network the dwarfs have been excavating beneath Ankh-Morpork's streets. A deadly puzzle is pulling Sam Vimes deep into the muck and mire of superstition, hatred, and fear—and perhaps all the way to Koom Valley itself.

Terry Pratchett's novels have sold more than forty million (give or take a few million) copies worldwide. lives in England.

Stephen Briggs has dramatized many of Terry Pratchett's novels and is the co-author of The Discworld Companion. He lives in England.