The Entropy Plague written by Jonathan Morris and directed by Ken Bentley

What's it about: A Great Darkness is spreading over E-Space. Entropy increases. In search of a last exit to anywhere, the TARDIS arrives on the power-less planet of Apollyon, where the scientist Pallister guards the only way out – a mysterious portal. But the portal needs power to open, and the only power Pallister can draw on is the energy contained within the molecular bonds of all living tissue... The Doctor, Nyssa, Tegan and Turlough soon learn that neither Pallister nor his ally, the space pirate Captain Branarack, will stop at murder to ensure their escape. But they're not the only menace on Apollyon. The Sandmen are coming – creatures that live on the life force; that live on death.  Death is the only way out into N-Space. Death, or sacrifice. But whose death? Whose sacrifice?

An English Gentleman: It almost seems a pity that the fifth Doctor, Nyssa, Tegan and Turlough adventures might be coming to end just as the writers have gotten a firm grasp on all four characters. The characterisation of the regulars in Equilibrium was authentic and engaging but The Entropy Plague goes one better. Morris puts the four characters into a desperate situation and their feelings for each other all bubble to the surface in unexpected ways. It's potent stuff, the sort of material that could only be dished out at an important crossroads. Davison's Doctor is dominant and authoritative, Sutton's Nyssa is wise and thoughtful, Fielding's Tegan is resourceful and witty and Strickson's Turlough proves delightfully slippery but still heroic at times. Everyone has been considered and given a fair slice of the action but independent of each other and together. Since this is final story in this run for the four characters together it seems right that they should head into the sunset on a high.

He might be the softest of Doctors but number five often stumbles when it comes to breaking bad news and being open with people. Mind you having to tell a grown man who lost his mother from childhood that he will never clap eyes on her again is rather more difficult than telling a stroppy Australian that she has landed at Heathrow airport. He takes full responsibility for Nyssa's situation and is willing to explain. There is definitely a method to his madness to being so nice, look at how easily he gains the trust of Cherry-Ann in the cell. He's also pretty desperate and is willing to work with madmen in order to escape this impossible situation. Perhaps Tegan's words touched him to some degree but the most sacrificial (aside from perhaps McGann) of Doctors is willing to step up and give his life so the others can escape. An entirely selfless act. He's furiously angry with Adric when he seems to suggest that there should have been another way. He would have done everything in his power to have Nyssa by his side again. He would never admit it openly but there was far more to their relationship than just friendship. I don't think it was ever a sexual attraction but I think he was emotionally involved with her on a very complex level.

Alien Orphan: The Entropy Plague opens with a big revelation, that Nyssa is never going to see her children again. After asking us to invest in a character thread for this many years you had better hope that this promise is paid off. There is a big difference between fighting a disease that is ravaging through the universe and fighting entropy itself and Nyssa has the medical know how to recognise that one can be conquered and the other is simply an unpleasant fact of life. All these years and she is still putting other people first and herself last. It is built into the core of her character and it will be her downfall but she still knows she is doing the right thing. It was how she was brought up and what better way to pay tribute to all those people who have gone? She wouldn't want to be any other way. Who can do the most good in E-Space when it is ravaged with disease? He might be called the Doctor but she is the qualified one and helping people and curing the sick is what she has been trained to do. If that means she has to sacrifice her freedom again and the chance to see her children then that is still what she has to do. It's in the core of her being to be altruistic. Her rejuvenation has been reversed and there is no cure, she's an old woman again and she is staying that way.

Mouth on Legs: Everybody is taking the piss out of Tegan again so naturally I am as happy as Larry. Tegan is furious that the Doctor would even consider the sacrifice of a person in order to secure them a way home, let alone consider it a viable option. I'm really pleased that Tegan asked the question of Nyssa's sacrifice, pointing out that she is seeming to prioritise the people of E-Space over her own children. It is moments like that where her no-nonsense attitude really come into their own.

Over the Shoulder: Naturally it is Turlough who outright suggests that they sacrifice somebody to escape E-Space, one life for many are the kind of odds he can live with. Just as obviously he doesn't volunteer his own services. He is willing to put value on lives and weigh up someone who is less worth living than others, like Brannigan.

Standout Performance: All of the regulars have a great stab at the narration but Davison and Sutton come out on top. Davison is the consummate actor and always raises his game when the material is strong and Sutton takes every emotional opportunity, enjoying the chance to strip away Nyssa's icy exterior and show the mother, friend and beating heart beneath.

Sparkling Dialogue: 'I'm afraid you're never going to see your mother again.'

'They've got Tegan!' 'Yes. I'm not sure who to feel sorry for most.'

'You have to let me do this, Doctor. You have to let me be the one who stays behind!'

'I will regret this for as long as I live...'

Great Ideas: An unusual step is made to have this story narrated throughout with the Doctor, Tegan, Turlough and Nyssa all recounting their story to Adric over the space of an episode. It has never been tried before and I found it a very successful approach, allowing us to get involved with the action in a very intimate way through the eyes of our heroes. If the TARDIS runs out of power she will simply drift on through space until she hits something. A shanty town thick with a party atmosphere of momento mori and bathed in the sickly glow of a red sun, Jonny Morris sure knows how to conjure up a potent image in audio. A land of the dead where people from every corner of E-Space have congregated for one final knees up. There is a great darkness spreading across the heavens, the hungry night. Any energy from this planet is drawn through the portal like water down a plughole, not just from this world but from the entire universe. E-Space is experiencing both dimensional contraction and heat death. The portal is like a whirlpool, viewed from the front it is like looking down Niagara Falls but viewed from the side it is two dimensional. The entropy Plague is the blight of the universe, on some worlds it is known as the Wasting but on others it is known as death. It makes people decay away. It's nice to see Morris engaging with the idea of entropy that was so much a part of season nineteen but doing his own thing with it. Nyssa makes a powerful point about fear of diseases and how it can lead people to do worse things than the disease itself. Imagine a marketplace ageing before you, the fruit and animals decaying before your very eyes. In order for something to go through the portal somebody has to die, a human battery so to speak. Men formed entirely of sand but with gaping holes for mouths. The Sandmen are a genuinely chilling creation, again in keeping with the idea of decay and things breaking down and become insubstantial. I would have loved to have seen these realised on screen, reaching out for men and tearing the flesh from their bones. Drawing all the energy and lifeforce out of people. The second law of dynamics is infection, incurable and unstoppable resulting in complete cellular decay and disintegration. People turn to dust but it doesn't always prove fatal, the plague transforming the carrier into something else. The entropy plague spreading amongst the pirates is terrifying, these jovial characters suddenly gripped with cold fear.

Audio Landscape: A stunning amount of design work has been lavished on this story and I'm pleased as it is rather than important one. Andy Hardwick has pulled together something exceptional, a totally immersive and powerfully realised tale. At every step of the journey the sound effects compliment what the script is telling us and if you shut your eyes you can so easily conjure up this corner of E-Space in your head. The TARDIS crash landing, the glorious power draining noises from Death to the Daleks (including the cute little lights dimming), a hissing crashed spaceship, a screaming party atmosphere, clanking door, bubbling vats, the stomping hydraulics of the Sentinels, the chugging industrial nightmare of the machine, Tegan screaming into the distance, rain lashing, thunder, an arm dissolving, fabric tearing, the whirling, screaming, whipping storm of sandmen, shooting into a crowd, screams turning to sand, the portal destabilising, laughter, birdsong, scribbling. 

Musical Cues: Remember when Andy Hardwick recycled the same whirling, ethereal music during the latter Gary Russell period of the main range? It seems those days have long past and he has taken a good look at what other composers are doing and has upped his game immeasurably. Check out the exciting, fatalistic score as Tegan and Nyssa attempt to escape from the Sandmen, it is desperately exciting.

Isn't it Odd: I've heard complaints about the notion of pirates in this story but they are hardly played to a pantomime level and the only complaint I can see even remotely holding water is that they are a fairly similar bunch to the rogues who plagued the Doctor, Romana, Adric and K.9 when they were trying to escape E-Space. Perhaps it was deliberate then. My one sticking point was Pallister, who I never found particularly interesting, and so the first half of episode three was a little wearying as the action subsided and we got to know him (and his pirate cohorts) a little better.

Standout Scene: The scene where Nyssa offers her services as the power source is remarkably touching because it leads to a thread of loss between her and the Doctor that comes with quite unexpected poignancy. There was a fantastic moment in Equilibrium where Nyssa reaffirmed the good work that the Doctor has done that reminded me of the strength of affection between the two of them. But that was just the appetiser for the main course of upset that was to come. The Doctor tries to use Nyssa's children as a good reason for her to return to N-Space but there is a desperation in his voice that leads me to believe that it is also for his need. The narration where Nyssa rushing back to take Cherry-Ann's place in the interface quite took my breath away. I have been calling for the characters departure for some time because I genuinely feel all that can be done with her on audio has been accomplished and she has been treading water for sometime. Big Finish have managed to trump my criticism however because she clearly still had one thing to offer, a touching departure. And this was as good a departure as she could have hope for. Unlike Terminus where her exit felt quite sudden, this uses her decision in that story to provide a backbone for what she does for her friends here.

Result: 'It's like the world is coming to an end' 'Not just the world, the universe. We can only have a few hours left...' Genuinely very good, The Entropy Plague has caused me to reassess my opinion of the main range that has been on the wane of the past couple of years. That 24 month period can have hardly be called Big Finish's golden period but in the past six months of releases (from The Widow's Assassin to this adventure) I have scored the stories 10, 9, 7, 3, 8 and 9 which is leads me to believe that things could very well be on the up. What could essentially be called the 'older Nyssa arc', the period of adventures between Cobwebs and The Entropy Plague has been championed by Jonathan Morris and he has provided the run with it's strongest emotional beats and progressive moments. So it seems quite apt that he should be able to tie everything up as well, a pleasing bit of scheduling because he is also the strongest writer on Big Finish's roster. It is a substantial story in every sense of the term. So many adventures of late have been fairly hollow, uninspired retreads of older, better stories but the content that fills The Entropy Plague is dramatic, satisfying, detailed, vivid ad emotional. It's has enough character, creativity and drama to fill several tales. Morris is always good but it feels like he has worked his butt off on this one. You'll be assaulted with powerful imagery, life or death action, mind expanding ideas, frightening monsters and emotional goodbyes. Not every Doctor Who story could be as full on as this but in a range that felt as though it had given up trying this amount of impact is highly appreciated. There is a feeling of desperation to The Entropy Plague that few Doctor Who stories manage to muster. As a result of all these things the performances of Davison, Sutton, Fielding and Strickson elevate considerably and they are all given a chance to narrate the story for an episode. Come the final episode you will come to understand the depth of feeling that exists between these four. Only minor flaws hold this back from being an absolute classic (Pallister and a few moments where there is a little too much talk and little action) but on the whole The Entropy Plague is a stunning release and the sort of standout release I expect of the main range on a regular basis from now on. A story that makes you feel, the last scene left me in tears: 9/10