For Miriam Gardiner at her engagement party at the London home of her fianc? Lucius Stourbridge it should have been one of the happiest days of her life. But leaving suddenly Miriam disappears without a trace. Reluctant to cause a scandal Lucius seeks out William Monk & tells him that the only lead concerns their coachman Treadwell who is also missing. Monk not usually a sentimental man is moved by Lucius's distress & assumes that his recent marriage to Hester Latterly is to blame. When Treadwell's murdered body is found Monk becomes convinced that his death is linked to a terrible secret in Miriam's past that someone desperate keep it hidden has killed for & may well do so again unless he can stop them.