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.
Hoping to save their family and the citizens of Ferryport Landing from the evil plans of Mirror, Sabrina and Daphne Grimm seek counsel from the other magic mirrors, who advise them to join forces with the Scarlet Hand.
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.