Eleven hundred years after the apocalyptic destruction of the United States of America, peace between the remaining warring tribes has finally been achieved. Despite this peace, the Pelbar stronghold Threerivers retains its secretive and reclusive ways, keeping its distance from the other remaining tribes and guarding against change. A strict matriarchy, Threerivers remains the most conservative Pelbar community under the unquestioned and unyielding rule of its leader, Udge.Life in Threerivers continues without change until two young twin brothers, Brudoer and Gamwyn, accidentally initiate events that threaten the established order. The resulting chain of consequences sends Gamwyn on a quest to the far reaches of this postapocalyptic world. Within Threerivers, Brudoer's imprisonment threatens the long-established matriarchal rule of the Pelbar stronghold.The Fall of the Shell is the fourth book in the classic series of postapocalyptic novels about the people of Pelbar.

More than one thousand years in the future, the conservative borders of Pelbar society continue to crumble as the people of Pelbar conduct trade, form friendships, and intermarry with members of the tribes now settled peacefully around the citadel of Northwall. Not all agree with the changes, however, and long instead for the old times of conflict and rigid order. Igniting the tension is the discovery of a mysterious subterranean shelter, where the descendants of survivors of the long-ago nuclear war live. A young woman from the shelter and the shocking revelations she brings precipitate a crisis that will profoundly affect the futures of plainsmen and citadelfolk alike. The Dome in the Forest is the third volume and one of the most exciting tales in the Pelbar Cycle, a classic series of seven postapocalyptic novels about the people of Pelbar.