The Calling of the Grave is the fourth instalment in the Doctor David Hunter Series by Simon Beckett.
The book starts as a prequel to the entire series as it is set some time before the events of The Chemistry of Death, when David Hunter's wife and Daughter (Kara and Alice) are still alive.
Hunter is called out to examine locations for deposition sites of the victims of Jerome Monk, a rapist and killer who was known to have killed at least four people and buried their bodies on Dartmoor.
[1] Monk, who is serving time in Dartmoor prison for his crimes, agrees to help the investigation team find the bodies and he is brought out onto the moor.
[2] Eight years later, Monk escapes from prison and sets about targeting all those who were on that investigation and David Hunter finds himself on Dartmoor once again.