The Dark Tower IV: Wizard and Glass recap

Trapped aboard the insane monorail Blaine, Eddie destroys it by feeding it foolish, illogical riddles it cannot bear, and the ka-tet steps off into a version of Kansas emptied by a killer plague. Following the highway and a strange thinny toward a green glass palace, they rest, and Roland finally tells the story of his youth. As a teenager, freshly made a gunslinger, he was sent east to the quiet barony of Mejis with his friends Cuthbert and Alain to keep them safe from the rising war. There Roland fell in love with Susan Delgado, uncovered a conspiracy of hired killers supplying the rebel John Farson, and took a piece of the wizard's rainbow, a pink seeing-glass. The tale ends in tragedy: Susan is betrayed and burned, and the glass tricks Roland into a killing that scars him for life. Back in the present, the ka-tet reaches the green palace and confronts Randall Flagg, who mocks them and flees. They return to the path of the Beam.

So far, Roland Deschain, the last gunslinger of Gilead, has chased the man in black across a desert, sacrificed the boy Jake, and been told he must draw three companions on the road to the Dark Tower. At the Western Sea he drew Eddie Dean and Susannah Dean through doors from twentieth-century New York, and both became gunslingers-in-training and lovers. Roland's meddling in the past had split the boy Jake between death and survival, driving them both toward madness, until the ka-tet drew Jake back through a haunted house and healed the paradox, gaining the billy-bumbler Oy along the way. Following the path of a Beam toward the Tower, they crossed the ruined city of Lud and boarded Blaine, an insane sentient monorail that carried them across the poisoned waste lands under threat of death unless they could beat it at riddles.

Roland's long tale of Mejis closes in loss: his first love, Susan Delgado, is denounced by a witch and the townsfolk and burned alive at a harvest fire while Roland is lured away, and the pink seeing-glass he wins, Maerlyn's Grapefruit, shows him visions that lead him to kill his own mother by mistake. This grief helped forge the closed, relentless man he became. In the present, the ka-tet crosses the plague-emptied Kansas and reaches a green glass palace on the road, where they find Randall Flagg, the dark sorcerer behind so much of Roland's suffering, playing at being a wizard. He taunts them, warns them off the Tower, and escapes rather than face them. Shaken but unbroken, and now knowing one another far better, Roland, Eddie, Susannah, Jake, and Oy leave the palace and take up the path of the Beam again, their bond deepened and the Tower still ahead.