Nina, secretary of the lawyer Mr. Mendoza, is an imaginative liar. Because of her work, she has access to the will of an old millionaire who died naming as the sole beneficiary his daughter, the fruit of a love affair of youth. Only the millionaire's sister, the widow of Martiarena, knows who she is and where she lives. Nina decides to impersonate her and, to his astonishment, is recognized as the real daughter by the sister. But the housekeeper and the doctor of Mrs. Martiarena decide to resolve the situation.
