In Maine, Roland and Eddie recruit John Cullum, and then make their way back to Fedic, where the ka-tet is now reunited. Walter (known in other stories as Randall Flagg) has dreams of grandeur in which he plans to slay Mordred and use the birthmark on Mordred's heel to gain access to the Tower, but he is easily slain by the infant when Mordred sees through his lies.
Roland and his ka-tet travel to Thunderclap, then to the nearby Devar-Toi, to stop 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. The Gunslingers free the Breakers from their captors, but Eddie is mortally wounded after the battle and dies a short while later. Roland and Jake pause to mourn and then jump to Maine of 1999 along with Oy, in order to save the life of Stephen King (who is a secondary character in the book); the ka-tet have come to believe that for some unexplained reason, the success of their quest depends on King's surviving to write about it through his books.
They discover King about to be hit by a van. Jake pushes King out of the way but is killed in the process. Roland, heartbroken with the loss of the person he considers his true son, buries Jake and returns to Susannah in Fedic with Oy, where they depart and travel for weeks across freezing badlands toward the Tower.
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. Roland and Susannah are alerted to the danger by Stephen King, who drops clues directly into the book, enabling them to defeat the vampire. Patrick is freed and soon his special talent becomes evident: his drawings and paintings have the strange tendency to become reality. As their travels bring them nearer to the Dark Tower, Susannah comes to the conclusion that Roland needs to complete his journey without her. After discovering Patrick's magical abilities in his drawings, Susannah asks Patrick to draw a door she has seen in her dreams, which lead her out of this world. He does so and once it appears, Susannah says goodbye to Roland and crosses over to another world.(...)