Agatha Montgomery, the proprietress and guiding spirit of Bertram's Bower, a home for wayward young women, is considered a saint by all who know her. Agatha's brother, the Reverend Montgomery, also supports the home, lending his considerable reputation and fund-raising abilities to his sister's efforts. But when two residents of Bertram's Bower are brutally murdered on successive nights, it will take more than saintly reputations to stop the wave of fear engulging the city.

Agatha's childhood friend Caroline Ames gamely steps in, convincing her brother, Addington, to conduct an unofficial investigation. There are suspects aplenty: the cocky young typewriter salesman, whose advances were rebuffed by the first victim; the young Irish lad-of-all-trades seen "having worlds" with the second; and even the Matron of the Bower, who seems to hate the girls as much as she hates all men. The case becomes more complicated, however, when disturbing rumors begin to circulate about the Reverend, and Agatha appears to be hiding secrets behind her ever-proper, kindly demeanor.

In a search for answers that takes them from posh Beacon Hill to the gritty immigrant neighborhood of Boston's South End, Caroline and Addington come face-to-face with the deep-seated prejudices of Boston's upper class against the growing Irish population-a prejudice that may destroy the life of an innocent young man and puts the amateur sleuths themselvs in mortal danger. With the uncanny talent for recreating the atmosphere of Victorian Boston that she displayed in The Death of Colonel Mann, Cynthia Peale once again weaves an irresistible tale of murder and corruption in unlikely places.