The Dark Tower V: Wolves of the Calla recap

The ka-tet comes to Calla Bryn Sturgis, a farming town plagued once a generation by the Wolves, masked raiders who ride out of the east and carry off one child from every pair of twins, returning them ruined in mind and doomed to die young. Bound by the gunslinger's code, Roland, Eddie, Susannah, and Jake agree to help the town fight back. In the Calla they meet Father Callahan, a priest from another world who guards Black Thirteen, a malevolent seeing-glass, and through it the ka-tet travels to 1977 New York to protect a magic rose tied to the Tower and to secure it from a reluctant bookseller. Meanwhile Susannah is secretly pregnant with a demon-fathered child, and a hidden second self, Mia, has risen to carry and defend it. The town, armed and trained, ambushes the Wolves and destroys them, revealing them as robotic servants of the Tower's enemies. But in the victory's confusion, Mia slips away with Black Thirteen to give birth, and Jake and Callahan go after her.

So far, Roland Deschain, the last gunslinger of Gilead, has drawn his ka-tet to him on the road to the Dark Tower: Eddie Dean and Susannah Dean, brought from twentieth-century New York and now wed, and the boy Jake Chambers, twice bound to Roland and once returned from death, along with the billy-bumbler Oy. Together they destroyed the insane monorail Blaine and passed through a plague-ruined version of Kansas, where Roland told the sorrowful tale of his youth in Mejis, his lost first love Susan Delgado, and the dark sorcerer Randall Flagg, whom they later faced and who fled from them at a glass palace. Following the path of a Beam, the ka-tet continues toward the Tower, growing closer and more skilled, while the wider war between the Tower's servants and its enemies begins to close in around their road.

The people of Calla Bryn Sturgis, led and trained by the ka-tet, spring their ambush on the Wolves and wipe them out, exposing the raiders as mechanical servants sent to harvest something from the stolen twins for the Tower's enemies. The town is saved and its children spared, at the cost of some lives among the defenders. But the triumph is undercut: Susannah's hidden second self, Mia, seizes control and steals away with Black Thirteen, the deadly seeing-glass, using it to open a door to New York so she can give birth to the demon child she has claimed as her own. Jake, with Father Callahan and the billy-bumbler Oy, races after her, and the book ends with them following her trail toward a nest of the Tower's servants in the city, the ka-tet broken apart and Susannah carried off inside her own body just as the next crisis begins.