"Snape did it!" Harry’s retort was loud, and Narcissa’s blank pale blue-grey eyes rested on the pair of them. Harry’s lips flattened together and he led Hermione out into the hallway by the arm with a nod to Tonks and Lupin, shutting the door behind them. He picked up where he’d left off. "For years. Dumbledore was convinced Snape was on our side. Except he wasn’t. He was spying, for all those years. Insinuating himself with our side, getting all the inside information. Couldn’t Malfoy be doing that?"