| DI Jack Caffery is a young man searching for himself. Obsessed with the neighbour he believes murdered his 10 year-old brother in the 90s, Jack finds himself trying to right the wrongs of others - but at what cost? In an isolated house in Monmouthshire, the wealthy Anchor-Ferrers family find themselves the victims of a psychopath’s cruel games, trapped and terrorised. When the two narratives collide, it’s a thrilling, nail-biting and deeply disturbing race against time. | 
| Name | Character | Episodes | 
|---|---|---|
| Iwan Rheon | Molina | 6 | 
| Juliet Stevenson | Matilda Anchor-Ferrers | 6 | 
| Owen Teale | Oliver Anchor-Ferrers | 6 | 
| Sacha Dhawan | Honey | 6 | 
| Ukweli Roach | Jack Caffery | 6 | 
| Annes Elwy | Lucia Anchor-Ferrers | 6 | 
| Sian Reese-Williams | DI Maia Lincoln | 5 | 
| Tim Treloar | The Walking Man | 4 | 
| Karl Johnson | Colonel Frink | 3 | 
| Oscar Coleman | Young Jack | 3 | 
| Kai Owen | DI Matthews | 3 | 
| Amanda Drew | Supt Harper Driscoll | 2 | 
| Hywel Simons | Robbie | 2 | 
| Richard Elfyn | Mr Bell | 1 | 
| Caroline Berry | Doctor Diaz | 1 | 
| George Russo | DI Richards | 1 | 
| Hywel Morgan | Richard | 1 |