Roland Deschain and his ka-tet are bearing southeast through the forests of Mid-World on their quest for the Dark Tower. Their path takes them to the outskirts of Calla Bryn Sturgis. But beyond the tranquil farm town, the ground rises to the hulking darkness of Thunderclap, the source of a terrible affliction that is stealing the town's soul. The wolves of the Thunderclap and their unspeakable depredation are coming. To resist them is to risk all, but these are odds the gunslingers are used to. Their guns, however, will not be enough....