Mathias is under pressure; Meg Mathias his wife has turned up in Aberystwyth, and he’s under investigation by the IPCC following the death of Mari Davies in the last episode. When a bus driver’s body is found shot on an isolated mountainside, the investigation provides a welcome escape for DCI Mathias. The team have a suspect to question but Mathias believes he is an unlikely killer. In his current state of mind Mathias is fascinated by the life-style choices taken by ex-soldier John Bell. He also knows that he cannot avoid Meg for much longer.