The novel is set in Paris at the end of the 19th century. The focal point is the city's Opera, which is experiencing great glory during that period. However, in the basements of the magnificent building, far from the dazzling lights, a secret is hidden. Torture chambers, hidden passages, labyrinthine corridors, underground lakes, and catacombs compose a parallel world, ruled by the dark figure of Erik, the Phantom of the Opera. Erik, a deformed musician who oscillates between genius and madness, falls in love with the young soprano Christine. He becomes her teacher and protector, initiates her into the secrets of music, and helps her evolve into a great opera star. However, her love for the viscount Raoul and her repulsion when she sees his face ignite his jealousy and rage, leading him to abduct her. With the help of the Persian, an old acquaintance of Erik, Raoul will try to save his beloved and solve the mystery of his brother's murder, who was found dead the same night.