The treatment

A quiet residential street in south London.

A husband and wife are discovered, imprisoned in their own home. Badly dehydrated, they've been bound and beaten. He is close to death. But worse is to come: their young son is missing.

When Detective Inspector Jack Caffery is called in to investigate, the similarities with events in his own past make it impossible for him to view this new crime dispassionately.

And as he digs deeper - as he attempts to hold his own life together in the face of ever more disturbing revelations about both his past and his present - the real nightmare begins. . .