Y/N was the sort of person everyone assumed had been sorted into the wrong house. Bright smiles, endless kindness, and a habit of helping anyone who needed it made her seem more like a Hufflepuff than a Slytherin. To everyone around her, Y/N was sunshine wrapped in green and silver. Theodore Nott hated it. Or at least, that was what he told himself. While everyone else continued treating Y/N like Hogwarts' resident sweetheart, Theodore watched her more closely. He started seeing patterns where others saw coincidence. Every conversation, every smile, every perfectly chosen word seemed deliberate. She read rooms better than anyone. What begins as irritation grows into fascination, then tension, then something neither of them can escape. As Theodore falls harder and harder for the girl everyone else underestimates, he discovers the truth about Y/N: she is sunshine with a blade hidden behind her smile. And once he finally accepts every part of her, there is no saving him from falling completely. Especially when she has been quietly unraveling him from the very beginning.