The two figures had been on the bridge. He had grasped hold of her. To save her or to push her? Inspector William Monk is still feeling his way in a new post in the Thames River Police & knows he must solve the mystery to gain the respect of his men. Soon both he & Hester find themselves powerfully involved in the story of the dead woman Mary Havilland & her quest to vindicate her father found dead two months previously. An engineer working for the Argyll Construction Company James Havilland was convinced a major disaster would happen in the tunnels where London's desperately needed new sewer system was being built. Maddened by his obsession he'd apparently shot himself. Mary had never accepted that & now she was dead too. Was it chance or something more sinister?