Deeply Sown

So it was for the first Longbottom who swore an unbreakable vow, as it would be for all of her descendants. Neville was tired of being bullied and pushed around, constantly underestimated by everyone around him but he is determined to prove himself. What happens when he discovers a strange being wandering around the abandoned corridors of Hogwarts Castle? TR/NL Creature Fic!