Don Gallico is an inventor of stage magic effects who aspires to become a star in his own right. Just before his first performance his act is shut down by capricious manager Ross Ormond who wants Gallico’s brilliant buzz saw effect for the act of The Great Rinaldi, an established star. With this defeat, and the humiliation of having already lost his wife Claire to Ormond, Gallico decides it is time to take matters into his own hands.

In Victorian era London, the inhabitants of a family home with rented rooms upstairs fear the new lodger is Jack the Ripper.