The Last Adventure: The End of the Line by Simon Barnard & Paul Morris and directed by Nicholas Briggs

What's it about: The Doctor and his latest companion Constance investigate a commuter train that has lost its way...

Softer Six: This is it then, the beginning of the end for Sixie. Colin Baker has made some waves in the world of Doctor Who recently with his controversial interview in Doctor Who magazine and inflammatory tweets about a Radio Times article. It is true that his Doctor is not always held in high regard by the majority of fandom and that his era is often pointed at as a low point for the show. It's not a view that I share, I was a huge fan of Sixie even before he enjoyed his phenomenal renaissance with Big Finish but the way his character flourished on audio on reinforced what I already though about the character. Strong, determined, ruthlessly intelligent, emotional and a little bit crazy. The Doctor. And Colin has been a firm supporter of the show ever since his sacking and never given less than 100% of what has been asked of him. Regardless of recent events, I'm one of the biggest supporters of Sixie and Colin and this box set gets me very excited indeed. After Sixie's ignominious exit on the show it is time for one of the most colourful and exciting Doctor's to have his final story revealed. Just how will Big Finish bring his story to a close? He's taking charge in his immutable way, stepping into the aftermath of a crisis and investigating the circumstances. Being lost is just a state of mind, the Doctor finds that whichever direction he follows something always turns up. His sense of direction might be eccentric but it's never concentric. Even if Jack is lying and he is a danger to them, the Doctor cannot take the chance that somebody might be harmed either way. He can't stand bureaucratic bafflegab and takes every opportunity to mock it. All this talk of alternative universes leads the Doctor to discuss darker versions of yourself and his own unique take on that idea in the Valeyard. We're taking steps towards that finale. He diagnoses the Master as utterly mad for wanting to control all realities but then we all knew he was nutty as squirrel shit, right?. Despite everything, despite their rivalry and hatred for one another...the Master needs the Doctor's help. 'Forget you, Mrs Clarke? Never!' he laments as he agrees to help his foe in order for his friend to survive. There are some planets where the Doctor's coat is considered the epitome of understatement.

Constant Companion: Leave it to Big Finish to bring the release of this box set forwards and shoehorn an adventure with Constance in before her introductory story is even upon us. It's a bizarre marketing strategy because it effectively renders her opening story moot and she could just be slipped into his adventures like Mel was, unceremoniously. Despite this little piece of timey wimey (sigh) magic, I have to say I am mightily excited about the introduction of this character. Miranda Raison is a very accomplished actress and looks like she belongs with Colin Baker on the covers and the character spec for Constance just screams of potential - a member of the Women's Royal Navy Service, icy cold and intelligent, brave and uncompromising. Somebody that comes with all the skills to cope with the Doctor's adventures but hasn't experienced the horrors of the universe yet. How does she fare in her 'first' adventure? Rather well as it goes. Constance is not afraid to make a dig or two at the sixth Doctor or to stand up to him, which is an entry requirement if you are going to be one of his companions. Her clipped, plummy tones and go to attitude are very appealing, similar to but very different from Charley Pollard because Constance is an adult (and a professional). She prefers to be called Mrs Clarke. The Doctor isn't afraid to let her go off into a dangerous situation and to leave her in charge of peoples lives. He clearly has a great deal of faith in her. Constance is smart enough to get her head around the idea of alternative universes and the implications for their situation here but is also willing to admit that there is more to the idea than she is able to comprehend. I'm looking forward to hearing more from her and that is all I can ask.

Standout Performance: This is an ensemble piece and they all acquit themselves beautifully. There wasn't one performance out of place. Especially the two grandiose villains sparring at the climax.

Sparkling Dialogue: 'To lose one Dave might be considered a misfortune but to lose three...'

'Let the other yous pay the price...'

'That's enough to rewrite the textbook on megalomania!'

Great Ideas: A train that gets lost in the fog and is discovered by the Doctor and Constance, with blood slick on the door. You wouldn't catch me going inside. The sun has failed to show up and time has stopped. A train station with platforms that keep multiplying at random. The ingredients for this story are very Sapphire and Steel and it conjures up a similar feeling of disquiet and claustrophobia that the best of their adventures did. A feeling of danger, of wrongness. How can there be multiple versions of the same person being killed over and over? Kettering Junction is not just a railway interchange, it is a dimensional interchange and it's breaking down. Parallel universes are not supposed to meet but here they are bleeding into one another. A multifarious multiverse of possibilities, as the Doctor puts it. If the Doctor doesn't put a stop to it soon there will be an infinite number of trains arriving with an infinite number of passengers to be killed. They will have run out of space before the convergence reaches infinity. Some of the alternative realities will be very nice places, others will be darker, rotten. Alice's realisation that she has always played the good girl when there have been alternative versions of her out there her were enjoying their lives and letting themselves go is a very dark moment. It's a dangerous path for your thoughts to go down. Why can't I be more like them? If they got away with it then why can't I? I can do what I want...free of consequences. What a terrifying notion it is to consider the idea of multiple versions of the same person and a primary timeline where only one should exist. Where all the others are expendable. Fodder. Ripe for murder because they are alternatives. Is there something in the fog that is driving everybody mad? The Parallel Sect are a mythical race of dimensional pioneers that traversed reality the way mere mortals cross the streets. The created a Reality Web, threading through the whole of infinity of parallel universes. An awe-inspiring notion. Imagine being able to negotiate such a web, to hop from one reality to another, from one universe to another. New management has moved in to take of the Parallel Sect, a figurehead who haunts the Doctor from his past. Can you guess who it is? Nope, it isn't the Valeyard. Very cleverly the writers have managed to slip in another returning villain right under the noses of the audience. Imagine the Master being handed the Reality Web, being able to stride dimensions and nip and tuck to his will. Spreading misery and despair in a billion realities. Platforms leading off in all directions, impossible to look at, let alone navigate. Passengers killing one another as they go mad with the absurdity and clarity of what has befallen them.

Audio Landscape: Footsteps on gravel, a train racing along the track, the sound of that weapon revealing the presence of you know who..., a knock on the door (amazing how scary that can be), a scream in the distance.

Musical Cues: Sinister and brooding for the most part, Howard Carter has been at this game too long now to deliver anything but excellence. He knows precisely the point where to stop too and let the silence do its work.

Isn't it Odd: Striding from the intimate to the epic might seem a little

Standout Scene: I haven't been chilled to the bone quite so much by an audio than when Hilary revealed that she killed Dave and why. It's remarkably creepy because the speech she is given to say attempts to justify her actions before the payoff of revealing what she has done. It's grounded in character and it's convincing and that is why it's so terrifying. 'I enjoyed killing him...so who wants to be next?'

Result: Creepy, thick with atmosphere and bolstered by fine performances, The End of the Line kicks off the Last Adventure set in real style.  At points this reminded me of Midnight; frightened, irrational characters trapped in a terrifying situation and it enjoys a similar feeling of fraughtness and claustrophobia. It has the added element of weirdness that I would usually associate with Sapphire and Steel; an unknowable menace hiding in the shadows, a dark and dank setting that isn't playing by the rules and some quirky twists that take you by surprise. It's populated with some vivid characters too who are superlatively brought to life by the cast. Doctor Who has explored the alternative universe concept in novels (oh boy did it overplay it in novels), in comic strip form and on the TV. Big Finish has even had a stab at it too in it's Unbound series. But I have never seen it handled quite like this before in such a disquieting, psychologically probing manner. It's a unique approach and I love that. I'm often surprised that when a series scales back the storytelling to just a few characters in a confined setting that you often get the most extraordinary results. The End of the Line confirms that assertion for its first two thirds before exploding into high concept heaven for the finale, opening out on a scale grander than perhaps any other Doctor Who story. The groundwork has been set for this epic. If you were hoping that Big Finish were going to pull out all the stops for Colin Baker's swansong then by the standards of this first story it looks like you might be very happy indeed: 9/10