Isabella, a young model, is murdered by a mysterious masked figure at a fashion house in Rome. When her diary, which details the house employees' many vices, disappears, the masked killer begins killing off all the models in and around the house to find it.

Surrounded by fans and sceptics, grizzled director J.J. "Jake" Hannaford returns from years abroad in Europe to a changed Hollywood, where he attempts to make his innovative comeback film. This film was started in 1970 but never completed during Welles's lifetime.