Ranger's Apprentice - The Kings of Clonmel

Will is at the annual Ranger Gathering, but Halt is investigating mysterious events in the west. When he finally returns, he brings bad news. Hibernia is in turmoil. A false religious sect calling themselves the Outsiders is sowing confusion and inciting rebellion, and five of the six Hibernian kingdoms have already been overthrown. Now the sixth, the kingdom of Clonmel, is under threat, and Halt, Will, and Horace set out on a journey to help restore order. Will the secrets of Halt's past prove useful on their quest?
One Ranger can usually prevent a rebellion, but this time, even two may not be enough.