Sir John Fielding, the blind magistrate of Bow Street, has married the widow Katherine Durham. Some years ago he had persuaded the authorities to allow her son, Tom, to be conscripted into the Navy rather than be imprisoned for a youthful escapade. Now he is due to return to England after three years at sea, but his homecoming is marred by the death of an officer being deemed murder, not accident. As Tom is now part of his "eyes" Jeremy Proctor - and uncovers a web of conspiracy designed to make a scapegoat of an innocent man and allow a killer to get away with more than one murder.