The novel begins where The Waste Lands ended. After Jake, Eddie, Susannah and Roland fruitlessly riddle Blaine the Mono for several hours, Eddie defeats the mad computer by telling childish jokes. Blaine is unable to handle Eddie's "illogical" riddles, and short-circuits. The ka-tet leaves the city via the Kansas Turnpike, and as they camp one night next to an eerie dimensional hole which Roland calls a "thinny," the gunslinger tells his apprentices of his past, and his first encounter with a thinny.