Set a year after series one, we see former detective Huw, who, after surviving a brutal stabbing, believes he has finally escaped the psychological grip of serial killer Patrick, now safely behind bars. Retreating with his wife Alice to an isolated house by the sea, Huw is determined to rebuild a quiet life, far from the violence that nearly destroyed them. But peace, he soon realises, is an illusion.   

The cat and mouse thriller tells the story of Huw Miller, a police detective still haunted by the one case that he failed to solve – a stalker who taunted his town, mercilessly toying with his victims before eventually killing them. As Huw attempts to settle into retirement, the case is never far from his mind - and when new neighbour, Patrick Harbottle moves in and utters the chilling phrase ‘catch you later' – the sign off the stalker used to taunt Huw during the investigation – Huw is determined he's finally got his man.

What follows is a high stakes game of psychological chess between the two neighbours as Huw's world begins to crumble around him. Unable to bear the guilt of the stalker taking another victim under his nose, Huw risks everything to unearth the truth. But has he set his sights on the right man, or is his obsession pushing him ever closer to the brink?