Will and his friend Horace are chosen by the Rangers to do battle with the evil warlord Morgarath; but Morgarath and his legions make it over the once impassible eastern mountains with plans to to ambush the king's army.
Halt, Will, and Horace set out for Hibernia, where a quasi-religious group, the Outsiders, is sowing confusion and sedition, and they find that secrets from Halt's past may hold the key to restoring order before the last kingdom is undermined.