Unforgotten review: a satisfying ending that lingers after the credits roll

All the strands came together in a gripping finale, with a solution to the murder that was as convincing as it was clever

Nicola Walker as DCI Cassie Stuart and Sanjeev Bhaskar as DS Sunny Khan
A refreshing change … Nicola Walker as DCI Cassie Stuart and Sanjeev Bhaskar as DS Sunny Khan. Photograph: ITV

So, in the end, Unforgotten (ITV) equals Strangers on a Train, the Patricia Highsmith novel/Hitchcock film – I’ll do your murder if you do mine, so as not to get caught, hopefully. Except there are three of them here, and they are not on a train. Strangers in an Ealing psychiatric unit, then; that’s where Sara, Colin and Marion met and hatched their plan, because these strangers were victims of sexual abuse as children. It ain’t no Ealing comedy, that’s for sure.

I hadn’t guessed it, and I had thought about it a lot, since the end of the last episode when DCI Cassie Stuart told DS Sunny Khan she thought she had cracked it. (Just after he had had a crack at her, as it happens). Unforgotten does that – lingers, worrying you, after the end credits roll.

I have also enjoyed watching it the old-fashioned way, when it goes out (remember that?) because of the build-up in anticipation as Thursday night approaches, and because of the need to discuss it afterwards, even if the watercooler has been moved from the office to the Twittersphere. Perhaps scheduled TV and event TV can still find a home for more than sport and baking.

Some of the details are best not scrutinised too deeply: such as how Colin managed to string up Marion’s abusive dad in Highgate woods and make it look like suicide; or how Sara got Colin’s abusive Scout leader out on his boat, into the Clyde, then over the side. If that’s what she did.

But Unforgotten doesn’t go into those details and there is no real need for you to either. As a solution to the murder mystery, it is a convincing and clever one, as it was with the first series, but not too clever-clever, like Sherlock. All those strands come together in a satisfying knot.

Also clever is Cassie’s cracking of it – because their alibis were too good, and because they tried too hard to look as if they didn’t know each other. Remember that next time you kill someone: don’t make it too perfect, or your alibi too watertight. And don’t think that, just because you have got away with it for a quarter of a century, Cassie and Sunny won’t come knocking on the door one day.

Unforgotten is so much more than a satisfying murder mystery, though. It is such a human show. This one has been a thoughtful and timely examination of how sexual abuse affects children. Of the physical and irreparable mental damage it does, how it changes that person for ever. Of how hard it is to tell someone. Of the shame and guilt they feel, and the issues they may have in their own relationships. Of how they can sometimes recognise each other and are drawn together.

Colin’s impassioned speech to Cassie leaves you – and her – reeling and numb. He is a barrister, of course, and it is like a brilliant summing up, a final appeal – except that he is in a pub rather than a courtroom, he is appealing not to the jury but to the copper; and it is his own future that depends on it, not a client’s.

Then there is Marion’s to get through, too: more gruesome memories, revelations and details, about her own father, a past that never went away – and never will. Poor Sara, too, off to tell her husband, Hassan. I hope he is all right about her being a murderer.

It is not all grimness, though. Well, there is Nicola Walker’s DCI Stuart for one – such a convincing, real creation and performance. And a refreshing change from the current television standard; yes, she has issues, everyone has, but she is not a gloomy misanthrope with a cupboard full of skeletons and secrets and booze. Her relationship with Sanjeev Bhaskar’s DS Sunny Khan is lovely, sturdy enough to survive disagreements or an embarrassing drunken lunge. She is a great boss/daughter/mother, warm and calmly strong, but she will admit it if she is wrong about something.

Except, then, she is also magnanimous and wise. And now, case solved, it becomes about why people are sent to prison. As a deterrent, rehabilitation, or punishment? None of which Colin, Sarah and Marion need, so let’s leave it at that shall we; mum’s the word …

Again, that is quite a big ask of the viewer. But I’ll take it, because it seems like the right thing to do. And because it’s lovely.