The Chamber of secrets held far more secrets than just a monstrous Basilisk. After facing the beast, Harry Potter unwittingly stumbles upon one such secret. He wasn't the only Parselmouth in history.
AU. Post the battle of Hogwarts, Neville Longbottom comes out of his usual timid shell to take control of his life by its reins. Read along as he works hard to build something for himself, only to suddenly be faced with his grandmother's unwanted final play. (Slow-burn, EWE)