Twelve-year-old Jack Sawyer embarks on an epic quest--a walk from the seacoast of New Hampshire to the California coast--to find the talisman that will save his dying mother's life. Jack's journey takes him into the Territories, a parallel medieval universe, where most people from his own universe have analogs called "twinners." The queen of the Territories, Jack's mother's twinner, is also dying.

While Jake, Father Callahan, and Oy struggle to free Susannah Dean, whose body is possessed by a demon-mother named Mia, Roland and Eddie find themselves swept by magic to East Stoneham, Maine, in the summer of 1977.