Gaston Leroux's novel begins with Christine Daae, a beautiful chorus girl at the Paris Opera House. She has secretly been under the tutelage of her "Angel of Music", and in exchange for those lessons she has agreed never to love a man. This, of course, is not to be. Her childhood friend, the Vicomte Raoul de Chagny, visits her and is obviously taken with her. The so-called "Angel" notices her reciprocation, though she tried to hide it, and carries her off to his home beyond the lake beneath the Opera House.
Put two and two together, and it is plain to everyone that the Phantom was her music instructor, the Angel of Music. Christine's only means of escape is a promise that she will return to his home. He releases her, but she immediately takes refuge with the Vicomte. Their love (and secret engagement) is discovered and the Phantom's jealousy grows worse than ever.
He kidnaps her a second time. Raoul teams up with a nameless Persian who once knew Erik, the Opera Ghost, and the two seek out the house by the underground lake. They get trapped in the Torture Chamber, a room surrounded in mirrors with a tree in the center. It gives the illusion of an infinite jungle, and its prisoners go mad after only a few hours. Meanwhile, the Phantom has proposed to Christine. She is given a choice of two boxes to open, one in acceptance and one in declination. What she doesn't know is if she tells him no, that box is connected to a room containing enough explosive power to destroy the entire opera house, and everyone in it. She can hear Raoul and the Persian from her room but is unable to help them. She believes the only way to save her beloved is to marry Erik.
She is set free because of her willingness to marry him, even if only to save Raoul. He lets them both go, and the Persian, too. When visiting the Persian in the final chapter, the Phantom tells him that he is dying. "Of love... daroga... I am dying... of love..." he says. Three weeks later an advertisement appears in the news: Erik is dead.
Before the story ends, though, the Phantom is responsible for the deaths of Joseph Buquet, Comte Philippe de Chagny, and a poor woman the managers chose to replace Madame Giry, on whom the chandelier falls.
