On paper Save Me reads like your standard entry in the well-trod missing child genre and, if it weren’t for the excellent casting, there’s a chance it might have passed public attention by. It shouldn’t, though, because this is much more than the sum of its plot elements, and could turn into something really compelling.

We begin the first hour with Nelly (Lennie James, who also wrote and executive produced Save Me), someone who initially appears to be a fundamentally good man doing slightly dodgy things to get by. We assume that the woman he lives with is his partner, that his pleasant indifference to the different occupants of his council estate means he’s tolerant and “woke”, and his readiness to come to the defense of other locals indicative of a stand-up guy. Just a cheeky chappy, in other words.

The show’s version of Deptford feels so real and lived in, its weird and wonderful residents and general grey-ness expertly established in this first episode. That world-building will come in handy once the mystery and its accompanying drama really kicks in, but it’s enough to make the premiere episode stand out from the other more generic portrayals of British working class life on television.

But Nelly may have had us all fooled, and our assumptions are gradually turned on their heads. He’s squatting with the woman, and he’s sleeping around with at least three others. His forcefulness with the unwanted punters in his local might be hiding some more sinister tendencies, and there are hushed mentions of past indiscretions that raise a lot of red flags.

It’s only when he is arrested on suspicion of abduction that things start to unravel. The abduction is that of his estranged daughter Jody, who has grown up without knowing her biological father and disappeared while travelling to meet him. Nelly doesn’t appear to have knowledge of this meetup, but all the signs (as far as the police are concerned, anyway) point to him having been involved.

Things get foggier still when we see that Jody has grown up decidedly middle-class with her mother, Claire (Suranne Jones), and that her step-father may also be a bit of a wrong ‘un. That hardly matters, we see, because he’s the guy living in the massive house and Nelly is black, poor and probably homeless. The show doesn’t overtly state any of these things, but they can be inferred.

I truly believe that Lennie James is one of the UK’s best talents, and it’s so refreshing to see him take on something like Save Me. Not only as writer, but also as a performer. He’s wonderful as Nelly, all charm and barely-disguised desperation. He’s detached when it suits him, but it’s clear there’s a deeply emotional man behind the swagger and the smile. It’s a remarkably layered performance.

Save Me may stumble as the mystery takes over, but the characters are so well-drawn at this point that I hope it doesn’t. James has delivered a winner here, lending a freshness to what could have been just another British crime show.

Save Me airs weekly on Sky Atlantic.