Beginning where book six left off, Jake Chambers and Father Callahan battle the evil infestation within the Dixie Pig, a vampire lounge in New York City featuring roast human flesh and doors to other worlds.

Susannah shoots but fails to kill Mordred, eliminates other agents of the Crimson King, and escapes to meet up with Jake at the cross-dimensional door beneath the Dixie Pig which connects to Fedic.

Roland and his ka-tet travel to Thunderclap, then to the nearby Devar-Toi, to help a group of psychics known as Breakers who are allowing their telepathic abilities to be used to break away at the beams that support the Tower.

Ted Brautigan and Dinky Earnshaw assist the gunslingers with information and weapons, and reunite Roland with his old friend Sheemie Ruiz from Mejis.

Roland, heartbroken with the loss of his adoptive son, buries Jake and returns with Oy to Susannah in Fedic, via the Dixie Pig, after paying a visit to the Tet Corporation.

Along the way, they find Patrick Danville, a young man imprisoned by someone who calls himself Joe Collins but is really a psychic vampire named Dandelo.

In a final "Coda" section, King urges the reader to close the book at this point, consider the story finished with a happy ending, and not venture inside the Tower with Roland.

Roland instantly realizes, to his horror, that he has reached the Tower countless times before, and is trapped in Ka's wheel as punishment for his ruthlessness and killing.

The only difference is that, this time, Roland possesses the Horn of Eld, which in the previous incarnation he had left lying on the ground after the Battle of Jericho Hill.

Roland hears the voice of Gan, whispering that, if he reaches the Tower again, perhaps this time the result will be different; there may yet be rest and redemption, if he stands true.