Cambridge, 1898. When an unidentified young woman is found floating in the river, journalist Patrick O'Sullivan calls on the one woman he is sure will solve the mystery: Mrs Vanessa Weatherburn. With a victim as well as a murderer to identify, she knows it will be no easy task. Forced to go undercover while investigating the owners of Heffer's bookshop, and helped along by the cream of Cambridge's academic community, Vanessa's fourth investigation (after The Library Paradox) will require all her skills to reel in the killer.