A blood-soaked hammer is discovered in a lorryload of wood delivered to a local pub. DI Shona Oliver appears to have a murder weapon, but where is the victim?

Then a call comes in that local forest ranger and ex-soldier John MacFarlane isn't answering his phone. There's no sign of MacFarlane at his cottage, and the only clue the team have to go on is a bloody trail in the snow which ends abruptly and leads to nowhere.

A manhunt begins. It seems something from MacFarlance's past may have caught up with him. But what exactly is unclear.

And Shona has her own past to contend with when someone from long ago makes an unexpected reappearance. Can she keep her head in the game?