Forensic archaeologist Ruth Galloway has excavated a body from the grounds of Norwich Castle; it's believed to be that of infamous Victorian murderess Jemima Green, who was hanged in 1867 for the murder of five children in her care. DCI Harry Nelson is immersed in the case of three infants found dead, one after the other, in their King's Lynn home. But then a child goes missing. Could the abduction be linked to the long-dead Mother Hook?