In the eighteenth-century Rome, Don Pasquale Corneto, wants his young nephew Ernesto, dedicated to a wasteful social life, to marry a rich spinster, both to save on the expenses of his maintenance and to increase the family heritage.
After searching in vain through Europe for her boy after 1917, a Russian ballerina settles in with a Paris artist, which arouses the ire of the man's model.
Count De Cay is happily married to a beautiful woman loyal to him. During an innocent and fortuitous encounter with one of his ex-lovers, however, he is surprised by his elderly uncles, who warn the countess.
