When the Venice police failed to locate the missing Nayland Smith and Dr. Petrie, Kerrigan decided to continue the search alone. As he contemplates a more thorough search of the Palazzo Mori Fadia the gondolier returns and Kerrigan is amazed when Fadia claims that he knows the secret passages of the palazzo. Easily persuaded Kerrigan returns  and together they explore the subterranean passages then Fadia disappears mysteriously and Kerrigan stumbles in to a room which, seems heavily scented with the odor of hawthorn blossoms. Here Kerrigan comes face to face with the strange woman who played so vital a part in the murder of General Kinto. trying to apprehend her he falls in to a trap ingeniously concealed in the floor. When he regains consciousness he finds himself chained in a dungeon with Smith and Petrie...