Dr Sam Ryan investigates the deaths of two children, each of whom have a connection with the same violent man.

Sam confronts investigators with new information. Although initially met with incredulity, it results in a Kim's body being exhumed to see if the injuries to both girls are similar.

A badly decomposed body bears all the signs of a ritualistic killing. Sam follows the clues into the world of the occult.

Sam goes to Bird's girlfriend Fran, the one person who can explain what has been going on. Fran discloses that there had been a fifth friend, leading to a pivotal revelation.

Sam is called to the scene of a restaurant fire where DI Adams needs her help to identify a badly burnt body. It emerges that the prime suspect is one of Sam's students, who had come to her for advice recently, and Sam needs to decide whether to tell the police. Then when further tragedy strikes, both Sam and DI Adams must face up to their own demons and secrets.

Vietnamese refugee Tran tells the harrowing story of her family's nightmare journey across the South China Seas. The complex story of the guilt and fatherhood ends in tragedy, and forces Sam to face some of her own demons concerning her father.