Echoes written by Gary Russell and directed by Scott Handcock

What's it about: Trapped alone on the last Tube home, Dorian finds himself confronted by phantoms… but why have they waited until now to track him down?

The Painted Man: Since Dorian has come back to life it has disturbed something. His miraculous comeback is causing attention. He likes to keep himself to himself. When you have lived for several centuries you don't always recognise anachronisms when you see them. Dorian has lived a long and busy life...how could he be expected to remember the faces of all those whose paths he has crossed. Does he enjoy his immortality? It has its moments, but even those are growing few and far between. Even when he thought he has ended it, the portrait brought him back. They are linked and one cannot exist without the other. In order for Dorian to leave the world behind (an offer he sounds like he is considering) there is a bargain to be made. The painting has to be sacrificed, the symbol of the deal he entered into. Surrender the painting and get a free pardon to paradise. No matter how many false memories they try and plant in his head he would never betray the painting to anybody. He knows these aren't people who have walked into his life because he has a picture sharp memory of everybody who has died because of him. Creatures have started to stir because of his revival.

Standout Performance: Come on, it's Tracey Childs. How can you fail to be impressed? And she's only in a single scene. Nicola Bryant is on board too and she's using her natural accent (well a slightly upper class version of her natural accent) and like in The Church and the Crown, it is a delight. It proves there is far more to her than Peri.

Sparkling Dialogue: 'So what is this? A train ride to purgatory?'

'I prefer to think that life clings on to me.'

'You're telling me I can just leave the world behind?'

Great Ideas: I love the idea of a train station turning out to be a trap for Dorian. Quite apart from the fact that I am slightly addicted to stories set on trains (I'm practically Sheldon Cooper in that respect) there is something spectacularly creepy about that voice booming from the intercom ordering Dorian upon the train. In order for Dorian to pass this test he has to try and recall the faces of the phantoms that appear on the train, not any easy task given all the people he has met. Was it the portrait that brought Dorian back to life or was it something else? Something other? This is the first time that something like this has been hinted at in season three and going forward I think it is a very important piece of information. Was his resurrection somebody's design? And if so for what purpose? The people on the train are those who have stood by him whilst he has investigated strange and the bizarre happenings over the years.

Isn't it Odd: I think you have to be very certain of where you are going if you are trying to pull off a story that revels in the surreal. You cannot just have random things happening for apparently no reason, which is how this story comes across for much of its running time. Don't get me wrong it isn't offensive material or anything but for quite some time I wondered why I happened to be listening to it and how it fitted into the large whole of the running story this season is telling.

Standout Scene: Where has Dorian's soul gone?

Result: 'All aboard, Mr Gray...'' This feels like something quite different from Dorian, a decision to cohere the season into a running storyline rather than continue with standalone adventures. I think that every series needs to shake up the format every now and again and it is a testament to Dorian Gray's unique formula that adhering to what is common practice (a story arc) feels like a departure from the norm. Is this as exclusive as the scattershot settings from series one and two? No, but it is being delivered in as assured a fashion. Gary Russell's name isn't one that I crave for in the schedules (he did bring two of the worst audios to my mind - Zagreus and He Jests at Scars - to life) but his script for the last season of Dorian was exceptional, the best thing that I think he has ever written. This isn't quite as exceptional because it doesn't feel as though it has been written with quite the same passion as The Picture of Loretta Delphine and it enters into the realm of fantasy and dreams more perhaps than I think this series should. Saying that the dialogue is still excellent and the performances really help to sell the material and there are some important plot revelations that are vital to the season as a whole. It was perfectly entertaining to listen to but it didn't get under my skin in the way that the previous three instalments of the season did. The last five minutes promise great things for the future though, once the cards are all on the table. This is definitely a case of okay journey, great destination: 6/10