Huw Miller is a detective still haunted by the one case he couldn’t solve: a stalker who plagued his city, mercilessly toying with his victims before eventually killing them. As Huw tries to settle into retirement, the case is never far from his mind – and when his new neighbour, Patrick Harbottle, moves in and utters the chilling phrase “goodbye” – the signal the stalker used to tease Huw during the investigation – Huw is determined that he has finally caught his man.