Humphrey, Kris-The Armored Goretusk

When Leo opens his assignment envelope on his ninth birthday, two words stare back at him: TOP SECRET. But before he has time to ask any questions, he's whisked away beyond the Village Wall to meet his new boss, the Guardian. 
As the Guardian's apprentice, he must protect his village from the monsters that lurk in the surrounding forest. Armed with a slingshot, magical stones, and a strange map, Leo is given his first mission--to do battle with an angry armored goretusk.