This Gothic melodrama from Hammer Studios is in color, but the plot is basically the same as the two previous efforts. Instead of Paris, the action takes place at the Royal Opera House in London. The Phantom (Herbert Lom) is a facially disfigured musician/composer who had his opera stolen by a conniving composer, the lecherous Lord d'Arcy. The Phantom -- who lives in the sewer beneath the opera house -- has his dwarf assistant (Ian Wilson) kidnap Christine Charles (Heather Sears), the lead actress in Gough's production, with whom he has fallen in love, and trains her to become an opera singer, performing a work he has written. Meanwhile, Christine's fiance, Harry Hunter (Edward de Souza, researches the phantom's history and, after locating his whereabouts and finding him, decides to unmask the mysterious fellow.