The dismembered body of a small child is found on a Thames rubbish barge. A painstaking search through layers of decaying rubbish reveals some clues but a discovery during the post mortem is even more disturbing. The little boy's heart has been crudely removed from his body and it looks like his murder could be African ritualistic killing. The murdered child's parents have logged a missing persons report, but their priest prevents Vivien from making contact. Offering to act as their interpreter, the priest speaks on their behalf, but Vivien soon realises the parents do, in fact, speak English. Does the priest know more about the child's murder than he is letting on? And where is their younger child Francis?