The kidnapper of a young girl leaves a talking doll in her room which is diabolically designed to lead Murdoch on a quest that is designed by a manipulative, enigmatic and vindictive criminal from the detective's past.

Detective Murdoch investigates the death of a man found dead on a park bench. Dr. Grace initially determines that he was stabbed in the abdomen but subsequently concludes he was actually suffocated. He also has dried blood on his index finger and three pages from a Mark Twain novel on him. When he returns to the station Murdoch meets Owen Hume who reports that his employer, lawyer Randolph Sampson, has been missing for two days and subsequently identifies him as the man in the park. Meanwhile, Constable Crabtree investigates the disappearance of a corpse, that of Prof. Andrew Richardson, from the medical school. His brain was the object of a medical study by Dr.Dempsy who is researching the brains of highly intelligent people. When it turns out that Sampson and Richardson are the same person Murdoch learns that he's dealing with a group of admirers who wanted to see him in action so to speak. Julia continues her suffrage activities and lawyer Clara Brett Martin confirms that it's possible for a woman to run for elected office.