Paula, her son Carl, and his estranged partner Emily, join family members to mark the birthday of their missing son. As Carl fights to convince Emily to come home, new information comes to light about the missing boy, the implications of which are worse than anyone could have imagined.
| Actor | Role |
|---|---|
 Zawe AshtonEmily | Emily |
 Morgan WatkinsCarl | Carl |
 Julie GrahamPaula | Paula |
| LLara HonnorCarol | Carol |
 Annie AldingtonSandra | Sandra |
 Athena DroutisDebby | Debby |
| SStephen DavyDave | Dave |
| SSteve LatelyLen | Len |
| TTony ParkinOld Man | Old Man |
| KKari KleivCouple Woman | Couple Woman |
| AAndrew BentleyCouple Man | Couple Man |
 Jamie BeamishDCI Bryant (voice) | DCI Bryant (voice) |