Max, Natalia, Ernie and Harley, also known as The Grey Griffins, have been through a lot in the past year. They've fought evil fairies and stopped the Shadow King Oberon from taking over the world. They've unlocked Max's destiny as the Guardian of the Codex, a magic book that grants him incredible power. And they've teamed up with the mystical Templar knights to stop a band of werewolves, led by Max's billionaire father, from ushering in Armageddon. Now the Templar have reopened Iron Bridge Academy, a school to train young recruits in the fight against the forces of evil, and the Griffins enter a whole new world of adventure. Most of all, Ernie is happy to discover that the school is filled like changelings - humans infused with fairy blood and supernatural abilities - as he thought he was the only one. But before long, the four friends are caught in a plot by the evil Otto von Strife, an old Templar foe, who plans to kidnap changelings and transfer their souls into clockwork war machines in a plot to rip open the door between the human and fairy worlds.