Y/N has a secret. She’s obsessed with Mattheo Riddle. She knows his routines, watches him from across crowded rooms, keeps the things he accidentally leaves behind, and has collected more photographs of him than she’d ever admit. She’s careful. Or at least, she thinks she is. Because Mattheo has a secret of his own. He’s obsessed with Y/N. He knows her habits, memorizes her schedule, keeps everything she leaves behind, and watches her when he thinks she isn’t looking. Neither of them knows the other is doing it. But when Cedric Diggory starts pursuing Y/N and Romilda Vane sets her sights on Mattheo, their carefully hidden obsessions begin turning into something much darker. Jealousy. Possession. Secrets. And two people slowly realizing that the person they’ve been watching… has been watching them too.