A year ago, Max, Natalia, Ernie, and Harley were just regular kinds from Avalon, Minnesota, but that was before they learned that evil faeries, werewolves, and other unthinkable monsters existed just beyond our world. Now they are the Grey Griffins: monster hunters, celebrated heroes, and allies to the legendary Templar Knights--but even heroes have to go to school.

This year, they're attending Iron Bridge Academy, a school...