Young organ-builder Alan Starr, on his way into Boston's First Church of the Commonwealth, comes across a lone infant. The baby is soon identified as Charles, son of widowed, aspiring organist Rosie Hall, who lives next door to the church--and who has disappeared, leaving behind a pool of blood on the kitchen floor. Alan retains an interest in the child, tracks him to a seedy foster home, and enlists help from Homer Kelly, ex-cop turned Harvard professor (God in Concord, etc.), to try to find Rosie--a search the police have abandoned after questionable evidence of her death in a car fire. Meanwhile, church minister Martin Kraeger faces his own problems as he seeks to repair damages after a fire in which the sexton died. Permanent organist James Castle has taken a leave of absence. His job, hotly competed for by needy Philip Tower and gauche Barbara Inch, is inadvertently won by Alan, who has added to his burdens the rehabilitation of self-destructing, legendary organist Harold Oates. Alan's faith that Rosie lives is vindicated as the story draws to a crashing climax and a clutch of happy endings. The clever plot and its oversupply of lively, interesting characters barely survive the author's enthusiasm for Bach fugues, church architecture, and everything you really didn't need to know about organs. Her illustrations, on the other hand, are elegant, crisp, and mercifully without unnecessary embellishment.