A dead man's curse on a London party house seems to echo from 1780 to 1936.

To prove his thesis that any product--even one that doesn't exist--can be merchandized if it is advertised properly, a young man gets together with his father's savvy secretary to market a non-existent laundry soap. Complications ensue when his "product" turns out to be more successful than even he imagined--and now he has to deliver.