London, 1672. A vicious killer stalks the court of Charles II, inscribing the victims’ bodies with mysterious markings. Are the murders the random acts of a madman? Or the violent effects of a deeply hidden conspiracy? Cambridge, 2008. Teaching history at Trinity College is Claire Donovan’s dream come true --- until one of her colleagues is found dead on the banks of the River Cam. The only key to the professor’s unsolved murder is the 17th-century diary kept by his last research subject, Hannah Devlin, physician to the king’s mistress.