If you were referring to the BBC anthology series "The Missing" (Season 1, Episode 8) , titled "Till Death," this was the series finale where Tony Hughes finally confronts the truth about his son Oliver's disappearance in Russia.
: The events of the sequel, The Missing 8 , following corrupt journalist Sisoy Salas as he investigates the disappearance of his colleagues. Theoretical "Episode 8" Feature: The Second Sequel The Missing 8 Episode 8
The Missing Recap Season 1 Episode 8, "Till Death" - Collider If you were referring to the BBC anthology