When fifteen-year-old Will is rejected by battleschool, he becomes the reluctant apprentice to the mysterious Ranger Halt, and winds up protecting the kingdom from danger.
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.