Anne and Bob are a couple who have just settled in Paris and have decided to hold a dinner in which high society will meet. At the last moment Bob invites his son from the first marriage so that there will be thirteen place settings at the table instead of twelve. By simple superstition, he decides to add a place setting and asks his maid Maria to pretend to be a rich Spaniard. But, the excess of wine and a suggestive conversation make that Maria and a dealer of English art are attracted. Anne does not approve of this romance and has the firm intention to stop it however.