In Chapter 12 of The Phantom of the Opera, Christine and Raoul escape to the top of the building and stroll along the tin roof watching Paris below. The Phantom follows them without their knowing of it. Christine and Raoul speak of their plans to escape after Christine's performance the next night, and Christine voices her fears and apprehensions that when the moment would arrive, she would be unwilling or unable to flee with Raoul. She makes him promise to take her with him regardless.
Then Christine tells Raoul the story of her encounters with the Phantom who taught her to sing. She describes their conversations and the visit where the Phantom, on his knees, declared his love for her and wept tears at her feet. As she and Raoul kiss, a great roar explodes in the night sky and, looking up, they see a great black shape high above them glaring down with blazing eyes and seemingly hanging on high by Apollo's string.