They have always scared him in the past - the Rangers, with their dark cloaks and shadowy ways. The villagers believe the Rangers practice magic that makes them invisible to ordinary people. And now 15-year-old Will, always small for his age, has been chosen as a Ranger's apprentice. What he doesn't yet realize is that the Rangers are the protectors of the kingdom. Highly trained in the skills of battle and surveillance, they fight the battles before the battles reach the people. And as Will is about to learn, there is a large battle brewing.

Will Treaty has come a long way from the small boy with dreams of knighthood. Life had other plans for him, and as an apprentice Ranger under Halt, he grew into a legend - the finest Ranger the kingdom has ever known. Yet Will is facing a tragic battle that has left him grim and alone. To add to his problems, the time has come to take on an apprentice of his own, and it's the last person he ever would have expected. Fighting his personal demons, Will has to win the trust and respect of his difficult new companion - a task that at times seems almost impossible.

They are outcasts. Hal, Stig, and the others - they are the boys the others want no part of. Skandians, as any reader of Ranger's Apprentice could tell you, are known for their size and strength. Not these boys. Yet that doesn't mean they don't have skills. And courage - which they will need every ounce of to do battle at sea against the other bands, the Wolves and the Sharks, in the ultimate race. The icy waters make for a treacherous playing field - especially when not everyone thinks of it as playing.

When Halt and Crowley discover that the ambitious Morgarath has been infiltrating the Rangers in order to corrupt the Corps, the young Rangers travel north to find Prince Duncan, seeking a royal warrant to stop Morgarath before it is too late. By weakening the Rangers, the most powerful force in support of the King, Morgarath plans to steal the throne.

Will and Maddie are in Toscana on a diplomatic mission when word comes of a cavalry force crossing the northern body and marauding through the countryside. At the behest of the emperor, the rangers head north to investigate. They discover that the invaders are a group of Temujai—a reconnaissance force searching for a place to penetrate and invade. So Will and Maddie must split up to gather forces and information in order to push the Temujai back once again.