A deer named Oisín tells the story of how his great-great-grandfather Finnian embarked on a magical adventure, leaving behind everything he knew to cross the West Wind Sea. Along the way, he and his friends face the Order of Wizards, a group of power-hungry wizards ransacking the realm to steal its magic. They meet a fascinating cast of characters including a witch, a sea monster, a Queen and her very hungry cat, and more.