The Babyons series consists of four long stories strung together by a supernatural thread and chronicling the family history of the Babyons over a period of about 200 years. The ghostly thread is introduced in the first story, "Third Personal Singular," a tale of 1750. James Babyon, engaged to marry his cousin Hariot, becomes suddenly averse from her and breaks the engagement within a month of the date set for the wedding. In a passionate scene in which the probable madness of Hariot is subtly suggested she pleads with him and, finding him adamant, cries that they are already married in soul and are inseparable. That his cousin actually is subject to fits of madness he does not learn until he is wedded to her companion Menella. He and Menella go to Europe to find everywhere that people have a curious fear of them; a fear which spreads to their servants and, when he learns that Hariot committed suicide, to Babyon himself. He regards himself directly responsible.