When Y/N Black returns to Hogwarts after a mysterious month-long disappearance, nothing is the same. Her best friend is gone from her side. Her brother is hiding the truth. And the girl she once called family is now holding her twin brother’s hand. Bound to her brother Regulus Black by a rare magical twin bond, Y/N can feel every lie, every guilt, every crack forming between them—but she can’t stop it from breaking. At the same time, she is forced to face the one person she has loved silently for years: Mattheo Riddle, who is finally no longer pretending he feels nothing. But love at Hogwarts is never simple. With friendships shattered, loyalties divided, and secrets buried beneath pure-blood expectations, Slytherin House becomes a battlefield of hearts. And in a world where everyone is connected by blood, betrayal cuts the deepest of all.