Will is small for his age, but agile and energetic. All his life, he has longed to be a warrior and to follow in the footsteps of the father he never knew, so he is devastated when he is rejected as an apprentice to Castle Redmont's Battleschool. He's no happier when he's assigned instead to the Ranger Corps, the Kingdom's secret service, as the Rangers are a mysterious group whose uncanny ability to move about unseen is thought by many to be the result of black magic.
Will begins training under the dour and enigmatic Halt, and reluctantly learns all the fieldcraft and archery he will need to become a fully-fledged Ranger. But Will soon finds himself needing all his new-found skills as he and Halt set off on a desperate mission to prevent the assassination of the King.