Count me among those who found this series to have much to recommend it. I'm glad I didn't let the low ratings deter me from watching.
Although I may be the only viewer who truly enjoyed the Eddie character, he struck me as a real, believable person who obviously had enough warmth and compassion so that David reached out to him for friendship and understanding. The scene with these two wounded men was well acted and quite touching.
Relationships can prove complicated in the best of times; in the case of a missing child who is later found dead they must be unbearably strained. I think the actors brilliantly portrayed the various emotional and ethical struggles they were facing. The continuing lies and complicity among the protagonists created a tenseness, albeit a frustrating one, that carried the story along to its conclusion.
And, yes, as someone mentioned, four episodes was just enough to develop the action, lead us astray, and reveal the truth.