The fictional hero of the book, David Small, is the unconventional leader of the Conservative Jewish congregation in the fictional suburban Massachusetts town of Barnard's Crossing. As the protagonist of a series of novels, Rabbi Small has wisdom, an unerring sense of Jewish tradition (which can at times put him at odds with the Jewish community when he believes that they are seriously deviating from Judaism) and all the good qualities of a detective sharpened by his Talmudic training, which enables him to see the third side of a problem. He is a devoted husband to his wife and (later in the series) father to his two children Jonathan and Hepsibah.
Small's logic, learned from the Talmud, plays an important part in the plots. Usually Small is drawn into the events when they involve a member of his congregation or Barnard's Crossing's Jewish community in general. Small has many troubles with his congregation and he is constantly at odds with at least one of its powerful members, usually the Temple President at the time.
Hugh Lanigan is the local police chief. Lanigan (a Catholic) and Small become friendly, and they often discuss religion over a cup of tea.