A Sunless Sea

William Monk has been working for the River Police for some time now, and was not surprised when a body was found on one of the piers.  However, it is the gruesome way the body was gutted that appals him.  His cohort, Orme, discovers where the woman comes from and they find out who she is.  However, that doesn't solve the crime.

As Monk continues his investigation he discovers that a doctor had been visiting the victim on a regular basis.  He then discovers that the doctor is a suicide victim, and that he had been researching the use of opium as a medicine.  Monk wonders at the connection of the two and widens his investigation.  Based on evidence or lack thereof, he wonders about the conclusion of suicide.

Monk's wife, Hester, starts an investigation of her own, looking into opium use throughout London.  She discovers that its use is endemic and that huge fortunes have been made as a result of its importation.

Monk's investigation points to the wife of the suicide as being the murderer of the woman.  She asks for Monk's friend Oliver Rathbone to be he solicitor.  Monk turns to his former superintendent, Runcorn, for help.  Their investigation points to the suicide in fact being murder.  When Monk is attacked it seems all the more suspect.

Rathbone is hard pressed in court to properly provide a defence.  He must do his utmost to waste time while Monk, Hester and Runcorn gather evidence and witnesses to help his case.  Author Anne Perry presents a surprising end to this Victorian murder mystery.