Jake is frightened by this news but not surprised; before being drawn from New York, he obtained two books from a bookstore owned by a man with the thought-provoking name of Calvin Tower. One is a book of riddles with the answers torn out. The other, Charlie the Choo-Choo, is a children's story with dark echoes of Mid-World. For one thing, the word char means death in the High Speech Roland grew up speaking in Gilead.

Aunt Talitha, the matriarch of River Crossing, gives Roland a silver cross to wear, and the travelers go their course. While crossing the dilapidated bridge which spans the River Send, Jake is abducted by a dying (and very dangerous) outlaw named Gasher. Gasher takes his young prisoner underground to the Tick-Tock Man, the last leader of the faction known as the Grays.

While Roland and Oy go after Jake, Eddie and Susannah find the Cradle of Lud, where Blaine the Mono awakes. Blaine is the last above ground tool of a vast computer system that lies beneath Lud, and Blaine has only one remaining interest: riddles. It promises to take the travelers to the monorail's final stop… if they can pose it a riddle it cannot solve. Otherwise, Blaine says, their trip will end in death: charyou tree.

Roland rescues Jake, leaving the Tick-Tock Man for dead. Yet Andrew Quick is not dead. Half-blind, hideously wounded about the face, he is rescued by a man who calls himself Richard Fannin. Fannin, however, also identifies himself as the Ageless Stranger, a demon of whom Roland has been warned.

The pilgrims continue their journey from the dying city of Lud, this time by monorail. The fact that the actual mind run-ning the mono exists in computers falling farther and farther behind them will make no difference one way or the other when the pink bullet jumps the decaying tracks somewhere along the Path of the Beam at a speed in excess of eight hundred miles an hour. Their one chance of survival is to pose Blaine a riddle which the computer cannot answer.