In the New York of the late 1970s, Jake Chambers is haunted by the same question: alive or dead? Which is he? After killing a gigantic bear named either Mir (so called by the old people who went in fear of it) or Shardik (by the Great Old Ones who built it), Roland, Eddie, and Susannah backtrack the beast and discover the Path of the Beam known as Shardik to Maturin, Bear to Turtle. There were once six of these Beams, running between the twelve portals which mark the edges of Mid-World. At the point where the Beams cross, at the center of Roland's world (and all worlds), stands the Dark Tower, the nexus of all where and when.

By now Eddie and Susannah are no longer prisoners in Roland's world. In love and well on the way to becoming gunslingers themselves, they are full participants in the quest and follow Roland, the last seppe-sai (death-seller), along the Path of Shardik, the Way of Maturin.

In a speaking ring not far from the Portal of the Bear, time is mended, paradox is ended, and the real third is drawn. Jake reenters Mid-World at the end of a perilous rite where all four-Jake, Eddie, Susannah, and Roland-remember the faces of their fathers and acquit themselves honorably. Not long after, the quartet becomes a quintet, when Jake befriends a billy-bumbler. Bumblers, which look like a combination of badger, raccoon, and dog, have a limited speaking ability. Jake names his new friend Oy.

The way of the pilgrims leads them toward the city of Lud, where the degenerate survivors of two old factions carry on an endless conflict. Before reaching the city, in the little town of River Crossing, they meet a few ancient survivors of the old days. They recognize Roland as a fellow survivor of those days before the world moved on, and honor him and his companions. The Old People also tell them of a monorail train which may still run from Lud and into the waste lands, along the Path of the Beam and toward the Dark Tower.