A young American couple inherits an English castle, only to find that it is haunted by the spirit of a disgraced ancestor, doomed to stay on the estate because of his cowardice. The only way he can escape is if one of his descendants performs an heroic act, something he intends to get the husband to do.

Ada Harris, a London charwoman in the 1950's, sees a Dior dress and decides that she's going to own one. First, she scrimps and saves her money, but when she has enough, and takes a trip to Paris, she learns that buying an original couture creation is a little harder than simply plunking down cash. Along the way to her goal, she manages to befriend a count, unite young lovers, and dodge customs.

Sherlock Holmes is brought back to life by Watson's female descendant after being cryogenically frozen for eighty years.