Talented Christine (Susanna Foster) is unaware that her singing lessons are being funded by a secret admirer, Enrique (Claude Rains), a mysterious violinist with a disfigured face. Christine's colleagues become suspicious when mysterious accidents start occurring at the Paris Opera House, as the deaths coincide with her meteoric rise to stardom. Christine's suitors, Raoul (Edgar Barrier) and Anatole (Nelson Eddy), brave the dark recesses of the opera house to find the true culprit.