Companion

In a hidden away village, people drink a special Potion when they turn 13. It either does nothing, and the villager in question usually goes to live in the nearby city of Edinburgh, where the Academy is secretly hidden away. Or, it gives you two powers, and an egg, which could hatch into any animal that has ever existed, with an intimate link to their partner's souls.
But Mia, a slightly unusual girl, has just changed her, and the village's life with her result.
It could change this girl's life.
Maybe forever.