Criss Cross written by Matt Fitton and directed by Ken Bentley

What's it about: Bletchley Park. Britain's most secret weapon in the Second World War. Inside draughty huts, the earliest computers clatter day and night, decoding enemy transmissions and revealing intelligence crucial to the country's defence. Leading WREN Mrs Constance Clarke directs her charges to provide vital assistance to the boffins stationed in the Manor House. But a recent arrival among the code-breakers, the mysterious Dr Smith, has attracted the attention of MI5's spy catchers... Over in mainland Europe, Nazi agents are briefed, covert operations planned, and a German submarine embarks on a very secret mission. As encrypted radio waves criss-cross the planet, unearthly forces stir. And when certain ciphers are cracked, something will emerge to threaten all humanity, regardless of allegiance...

Softer Six: The first story to be released after the sixth Doctor's memorable swansong in The Brink of Death and I guess the question on everybody's lips is there anything new to say about the character? Criss Cross answers with a firm yes, introducing the Doctor firmly entrenched in the story as it begins, sans TARDIS and setting up shop at Bletchley Park. It's so out of the ordinary it gives the opening scenes a real sense of optimism for the sixth Doctor adventures. If they can continue in this vein 'ol Sixie will be in good shape for years to come. Adventuring on his own, he's in the market for a new companion and I can see precisely why Constance fits the bill as far as he is concerned. You can see the respect he has for her position and her ability immediately. He is driven and in a world of his own but he doesn't mean anybody any harm...sometimes he just forgets the niceties. By the end of their first conversation the Doctor states 'Thank you, Mrs Clarke. It's good to have you on board' when signposts their allegiance beyond this adventure. Even when he does plan to stick around for a while he tries not to display too prominent a profile. It's taken him a long while but he's come to realise that it pays to blend in (hence his sharp tweed suit on the cover). The TARDIS is as dead as a dodo, the Doctor is looking for an escape from history. He's bored and whilst he cannot leave the Earth he figures he may as well do some digging. It's a dangerous place to settle because suspicion is high of foreign spies and whilst he is a benevolent one he certainly does fit that description. Sometimes he makes the most undignified exits. The 'Mrs Clarke' affectation is cute but it serves a dramatic point too because when danger strikes the Doctor drops the informality and calls her by her name. He's signed the Official Secrets Act several times. For once he has been as discreet as he possibly can. The Doctor talks about having friends in high places and we'll be hearing from that particular politician in Big Finish adventures soon. Constance wonders if the Doctor should invent a better cover story than the notion that he is a benevolent alien from outer space here to aid the human race. Maybe she has a point. For the Doctor, Bletchley almost puts Logopolis to shame and human ingenuity never ceases to amaze him.

Constant Companion: 'I'll never cease to be amazed at what Britain can achieve with an ounce of gumption and a modicum of application!' The first we hear of Constance she is barking orders at her girls in a concise, clipped manner. It sums her up rather well. No-nonsense, ready for action and not willing to beat around the bush. Just like Evelyn, it looks like the sixth Doctor might have met his match. Constance wont be placated when she thinks an injustice is being committed and it forces the Doctor to be the gentler character as a result. I think she might bring the best out in him. The first conversation they have Constance is having a go at the Doctor and he apologises for his thoughtlessness - you see what I mean? She will look after her girls even if it means butting heads with the male boffins at work in the war effort. She knows better than to ask officials about top secret work...but it still doesn't stop her. Henry Clarke was posted to special duties last November and Constance hasn't heard a thing since the start of the year. Are his circumstances fatal? She feels a little giddy after her first trip in the TARDIS, especially since it lands on its side and yet she walks out horizontally. The Doctor practically lets slip that the war will be over next year but tries to cover his mistake but Constance isn't fooled. Constance is extremely proud of her girls and will take any opportunity to express her pride. In a period where men were sent off to war and women were expected to suddenly play their part professionally, it was a time to be proud of that emancipation. It wasn't a case that the Doctor allowed Constance on board, she practically press ganged him into it.

Standout Performance: Miranda Raison gives a wonderful performance as Constance, icy cool and professional for the most part but allowing that facade to slip when it comes to asking about her husband MIA or blanching at the insane notions that are thrown at her by the Doctor. Raison is a consummate professional and I'm sure she will continue to thaw as her relationship with the Doctor develops. But for now it is more like colleagues working together than friends which is certainly a new approach.

Sparkling Dialogue: 'Mrs Clarke you might assume this ship was riveted together I Sunderland but I can assure you that the TARDIS and I hail from even further afield' 'What Gateshead?'

'Actually you've lost a few inches round the middle, haven't you?' 'I beg your pardon, Dr Smith!' 'My Ship, she's shrunk to fit.'

'Hande hoch, Doc.'

Great Ideas: Such an evocative time, such a fascinating location. Bletchley Park during the Second World War immediately perks my interest and gets things off to a flying start. In sharp contrast with Terror of the Sontarans there is a great deal of mystery and tangible plot to be had immediately; the Doctor tracking signals, the ambiguity of Constance's husband fate, a British explosives criminal being press ganged by the Reich and the conundrum of the dead TARDIS. A man being killed by radio waves, flooding his mind? Something in the ether has scrambled the TARDISes systems and it tried to the Doctor before dropping like a stone to the Earth. Where better for the Doctor to track coded signals but at Bletchley? He's been working around the clock to detect the path of the interference to trace it back to its source so he can free the TARDIS from its grip. There is an alien ship under the sea off the British coast and it has sent out reconnaissance beacons - the golden eggs. The question of which side Mr Flint is on weaves throughout the story. With him openly admitting to playing for both sides his allegiance is always in question. A war taking place on a plane of existence that most people aren't even aware of. I have always wondered why Doctor Who doesn't do more of this sort of thing, something a little more abstract and interesting beyond our comprehension. I have always been of the belief that if alien life exists out there that it is so far beyond our comprehension there could be a war going on all around us without us even knowing about it. Fitton has tapped into that in a war of sound waves, an intriguing notion that bears dramatic fruit given the location. Whilst it is certainly a novel approach, it might be a little too conceptual for some. Who else could betray both his own people and their enemies to the Choudray? Agent Criss Cross isn't a double agent but a triple one!

Audio Landscape: Scribbling, morse code reaching out, telephones, typing, creaking beds, a dripping tap, popping a cork, pouring wine, a growling staff car, rain falling, squelching through mud, the TARDIS coughing into life, sonar, the ship buffeting as it hits the bottom of the ocean.

Musical Cues: A dramatic, bombastic score for the most part with a strong militaristic theme. It's a little overbearing at times (again the polar opposite of Terror of the Sontarans) but it certainly provided excitement in all the right places.

Isn't it Odd: What was it I said about Big Finish and the variations of the line 'it's trying to invade my mind!' This is the second story in a row that the Doctor has exclaimed as much, released on the same day.

Standout Scene: For me it was the moment when the Doctor steps aside and lets everybody inside the dead TARDIS. What shocked me was the echoing silence inside, the dearth of any kind of life. I thought I had seen every kind of 'steps into the TARDIS' scene imaginable but this one was unusually disquieting and original, despite the fact that we had been pre-warned. The TARDIS, dead? What a terrifying concept. Constance's reaction is novel, questioning why he was storing the TARDIS in his office in Bletchley when he could have stored the whole of his office inside the TARDIS.

Result: Criss Cross comes with the added boost of introducing a terrific new companion and as such has a 'beginning of a new era' feel to it. As a story it is a tale of two halves with the first two episodes proving riveting because of the shed load of mysteries there are to solve and the uniqueness of the setting and the Doctor's predicament. The second half is far more traditional fare but there is still something quite novel about the cast of characters being caught up in a war beyond their comprehension. There's a naturalism to how the period setting is conjured up that excited me, something about the code breaking work during WWII really gets my engine revving. After The Wrong Doctors and Criss Cross I do declare Matt Fitton as the finest writer of the sixth Doctor on Big Finish's payroll at this time. It used to be Rob Shearman and Jac Rayner but they have been nowhere to be seen for years in the main range. Fitton has risen through the ranks and stands tall as the writer he understands how to take the controversial incarnation and give him a deliciously prominent role, fill his mouth with characterful, witty and smart lines and put him in some unusual and enjoyable situations. Sixie's role in episode one is an absolute delight and pairing him up with the equally formidable Constance Clarke gives Criss Cross a very strong foundation before we even reach the plot. Beyond the introductory episode there is nothing groundbreaking going on in this adventure but it is an engaging historical piece, crackling with energy and packed with fine performances. If you thought the main range had abandoned producing this kind of rock solid affair then think again, this is a fine Doctor Who adventure where the regulars compliment the story being told perfectly. I can't wait to see what Colin Baker and Miranda Raison bring to the table next month, it's a relationship that I think will yield some interesting results: 8/10