The inestimable Canterbury on DWF has posted a spoiler summary for the specials. Here is a cut-down version (really!), in two parts without the references and links etc:
Schedule
Remaining specials are 60, 60 and 75 minutes long. RTD: “No exact date yet but 4.16 will be seen before Christmas" (“not Halloween” and "probably one in Novemberish") followed by "a huge two-part finale at Christmas".
Locations and sets
RTD: Each special is very different and the locations are very different; that (after PotD) there would be visits to four more planets. (It appears that the only filming outside the UK for the specials is that done for "Planet of the Dead" in Dubai.)
EPISODES
4:16 The Waters of Mars Written by Russell T. Davies and Phil Ford Directed by Graeme Harper
Companion: Lindsay Duncan (Adelaide)
Cast: Peter O' Brien; Chook Sibtain; Aleksander Mikic; Cosima Shaw; Gemma Chan; Michael Goldsmith; Alan Ruscoe; Sharon Duncan Brewster; Paul Kasey
Characters, Villains and Casting Information
Diana Chire has been cast as "Allegra" in a 2009 production of DW, directed by Graeme Harper. No confirmation, so not added to cast list.
Lindsay Duncan will play the companion role; she will play Adelaide – the Doctor's cleverest and most strong-minded companion yet, who is head of the Mars Base and doesn't take kindly to an uninvited appearance by The Doctor.
Peter O’Brien plays Ed, Adelaide’s second-in-command, and the main villain; Gemma Chan will be playing "Mia Bennett" (also a villain); Alan Ruscoe playing ‘Andy Stone’.
Paul Kasey seen on set (Victoria Place) playing Ood Sigma.
"Other crew members are called Yuri, Ed and Mia, and the Wall-E robot is called Gadget."
The characters from this episode do not carry over into the two-part finale; though "there's a very strong link between the last three specials. It's not a three-parter, but there's a strong connection." (RTD)
Plot
Treatment for the second special contains the words 'oxygen', 'probe' and 'tree'. The script contains the words 'Emily', 'pipes', 'carrots', 'legend', 'gadget' and 'concerto' and the phrase 'the map of the Water Snake Wormholes'. Phil Ford described his script as "scary, dark and claustrophobic". The monster is called ‘The Flood’, though we don't find out what the monster is (as in Midnight).
Adelaide's daughter back on Earth is called Emily. The base is on Mars, not in space above it, and the TARDIS lands there and the Doctor is arrested by the robot before the titles roll.
Set reports
Night filming in a quarry: The TARDIS is all lit up and there is some action involving a number of naked flames (inside some type of structure). Some kind of caterpillar tracked machine or robot gliding through the flames. As it glides through there is an explosion.
Filming in a quarry: DT (or someone very like him!) is present, and wearing an orange spacesuit (as last seen in "The Impossible Planet"). A HUGE (and VERY loud) explosion, which formed a giant mushroom cloud and left a huge black smoke ring in the sky. Man in orange spacesuit as seen in Impossible Planet, almost certainly DT's stunt double, runs away from the explosion (in this case, green screen). He jumps on a trampoline and lands on a crash mat. Man in said spacesuit wakes up amongst a load of rubble. And slowly walks forward. This looks like it is DT (sideburns visible through the visor).
Victoria Place, Newport: Filming is on a snow covered Victoria Place. Street signs report this is a congestion charge zone with fines of 3000 yen, and also that it's a low emissions zone, hydrogen powered vehicles only. No Christmas trees or decorations in evidence; all windows are lit but draped. Filming features DT (blue suit), Lindsay Duncan and two others, Emma Chan and a young man. The clothes of the companions have a 'guerilla/freedom fighter' look; LD carries a small holster with a gun on her belt.
Filming also features a large white and silver robot (looking much like the one from the Taffswell quarry filming interacting with the four. The robot has "GADGET" written on its front. Snow is lying on the ground as DT and the other three step out of the Tardis. Doctor: "Aww it's snowing, I love snow!" The other male actor holds out his hands to feel it falling and says 'It's not snow...'
LD goes up the steps of one of the houses. DT flashes his sonic at the house. A blue light flashes for an instant in the house's window. "In the filming we are trying to suggest 10 Victoria Place is an empty property. It should feel quite dark and lonely".
AN OOD! Paul Kasey dressed as Ood Sigma. He doesn't interact with anyone, he just seems to appear.
DT goes back to the TARDIS, Two versions shot - one where he just opens the door and goes in, the other where he hears something, turns, looks a bit non plussed then turns the other way (towards the right, past the robot), sees something and collapses slowly to his knees (facing the robot).He then gets up, goes to the door of the TARDIS, looks straight out and then goes in and bangs the door shut. Ood Sigma was not in these scenes. Whatever the Doctor was looking at was not present at time of filming.
4:17TITLE TBA / 4:18 The End of Time Written by Russell T. Davies Directed by Euros Lynn
Characters, Villains and Casting
Captain Jack confirmed (by DT) as returning; as is John Simm’s Master.
Bernard Cribbins announced as Wilf, who is the Doctor’s companion (also seen on set). Catherine Tate (Donna), Jacqueline King (Sylvia), June Whitfield (‘Minnie Hooper’), David Harewood confirmed (and also seen on set). Alexandra Moen is back as Lucy Saxon.
Claire Bloom originally seen on set; claima she is "playing the intergalactic Time Lord's mother."
Jessica Hynes seen on set. The "bookshop" filming strongly suggests her character is Verity Newman. Images of her book "The Journal of Impossible Things" suggest a link between her character and the events of "Human Nature".
Billie Piper and Camille Coduri seen on set - "Powell Estate" filming strongly suggests they’re playing Rose and Jackie Tyler.
Elisabeth Sladen and Tommy Knight seen on set - "Bannerman Road" filming strongly suggests they're playing Sarah-Jane and Luke Smith.
Karl Collins and Barry Howard seen on set; Russell Tovey (Midshipman Alonzo) seen going into filming.
Timothy Dalton confirmed. "To play a baddie in one of David Tennant’s final episodes" says The Sun. Seen in a leaked photo wearing Timelord robes with the seal of Rasillon. RTD said that footage screened at Comic-Con included the voice of Timothy Dalton as the Narrator.
Sinead Keenan is confirmed by her agent as appearing in the finale. Lawry Lewin is playing a "geeky" character in a "pivotal role" in the finale, "his character is said to provide ‘a bit of a comedy turn’" and is also apparently an alien. Roger Bailey cast as a "Time Lord" and "Leader of Council". Sylvia Seymour cast as Miss Trefusis. Teresa Banham cast as "Governor".
Plot
The script for this episode contains the words The Gate, Naismith, Partisan, Carnival, Beijing and the phrase "something is coming". "Dark forces are gathering. The Gate is waiting, and life will never be the same again." RTD: "It's not quite as easy to guess what's happening as you think - there's nightmare sequences, and layers of fantasy, because the Doctor's coming to the end of his time.
"RTD and co are wanting to go out not only with a big bang but an emotionally challenging episode. So not only is Ten regenerating but the companion for the two episodes will also die at the end of the episode."
DT: "But that's going to come back in a big way in the final stories. The Doctor being the last of his kind, or nearly the last of his kind." "He's making hard choices and he's riddled with remorse for what happened to his people and the part he played in that. Which we'll learn a little bit more about before I disappear. Not that much, just a little. It's not a three-part miniseries starring Paul McGann. I think he's tortured. He travels time and space trying to make it better—literally, it's like he's the Doctor--and then the consequences of that are not always as he'd wish them to be."
DT: "The Doctor himself is also slightly on the run from himself, and on the run from the inevitable, so he's trying not to get too close to anyone. So, it's important that there is a revolving door of confidence for him. But, getting to see BC in that final story is so brilliant and moving. He's just such a great actor, and that was a great finish to the story, for me. You get these wonderful scenes of these two old men. The Doctor is a lot older than Wilf, and yet the two of them get to sit down and discuss life in a way that we've never seen the Doctor be able to do before."
"The "Part One" cliffhanger is "on a par" with that of "The Stolen Earth"."
Alien Invasion?
Set reports noted scenes in which David Harewood looks at the sky and falls to his knees; plus scenes outside Donna's house where people look at the sky and panic, and later seem relieved.
RTD: "And then, that final story becomes epic, almost like a fairytale. But, it's really intimate, at the same time. It's got funny little aliens with green spikey faces, running around."
There is supposed to be a "'something' species.
Lewin's character is apparently an alien, though not necessarily a monster or involving prosthetics.
Knock Four Times?
"You be careful, because your song is ending, sir. It is returning, it is returning through the dark. And then... oh, but then... he will knock four times." - Carmen's warning to the Doctor, PotD
Julie Gardner: And as we know, David, he really does knock four times.
DT: Yeah, absolutely, and if you think you've figured out what that means, you're wrong!
JG: But when you do figure it out, it's a sad day.
"1. The Master doesn't regenerate. 2. Neither does he knock."
A time of Time Lords?
THE MASTER
Photographed on set wearing a black hoodie and with bleached blond hair.
"We won't see the Master until the final specials... water (or liquid of some sort) is involved in his... 'reconstitution'. No clones AFAIU. Unless Miss Trefusis has added something else to the mixture. "
Daily Star: The Master and battles the Doctor until one dies, resulting in a new Doctor.
There will be two regenerations - both the Doctor and Master regenerate. Neither wins, neither loses, but the how and why are a closely guarded secret. John is reported as telling a source, "I'm David's Master... I think if he goes, I should too... the thought of us being inseparable even at the end, when we die, is a great idea. It's how it should be!
The Master returns with the help of Harriet Jones, who originally picked up the ring, was in league with the Master at the time of "TSE", was not alone when using the Copper network and was not killed. She and the Osterhagen key play into the finale and something in the specials fulfils what the Ninth Doctor said about HJ's terms as prime minister heralding a golden age. Is Harriet alive? Phil Collinson says yes, RTD says no, Penelope Wilton says maybe.
The Master is trying to be "the saviour" of the Time Lords.
There is apparently a scene in one of the Specials where the Master creates a new world which he shows to the Doctor, who responds in horror 'BUT WHAT ABOUT ALL THE PEOPLE???'
LUCY SAXON
"Don't worry: Lucy (as we knew her) is back ... sobbing in a 'dungeon'... witnessing the 'reconstitution' of her hubby (which comes as rather a shock to her!). Although how long she survives beyond his return I don't know! As for the ring - wasn't Lucy already in custody when we saw 'the hand'? Other parties must be involved - my money is on the mysterious Miss Trefusis..."
"that if a wife has any common sense she will want to keep her eye on her husband, particularly if she's from something beginning with 'G', she has been asked her to do so and her husband's the Master " Specifically "The info I have is that she is a time lord agent and put in place to keep tabs on the Master. " "Think [...] that hand being Mrs Master"
OTHER TIMELORDS
"think ...flash backs to gallifreyan war rooms at the height of the time war at the start of the penultimate story with the time lords resurrecting the Master to send him in vs the Daleks - James Bond [Timothy Dalton] as the President of the Time Lords ....the sound of drums being a way for the time lords to keep track of their secret weapon [the Master] who they send in vs the Dalek emperor .... the time lords doing a time hop, skip and a jump when the signal goes dead...can you guess why the signal goes dead...does the title of a recent Killers track [Human] come to mind?”
The TARDIS destroyed
Set reports on filming of the 2010 specials that the TARDIS exterior has changed.
"the TARDIS is destroyed at the end of specials and Matt Smith's Doctor has to grow a new one - the exterior is back to classic TV series Unearthly Child era (NOT the Cushing movie version), with white windows and St John's ambulance apparel - the interior has roundrels and is split on two levels, console room and lab")
"-the regeneration occuring just outside the TARDIS while it is dematerialising causing it to crash and be destroyed." "… the TARDIS does explode during lift off. The Doctor is inside and it is destroyed around him."
The Regeneration
Suggested causes of the regeneration: The Master. The Doctor will battle the Master until one dies; the TARDIS, and "I might drop an anvil on his head. Or maybe a piano. A radioactive piano" (RTD teasing again).
RTD said that he couldn't really talk about the regeneration without...talking about the regeneration (and hence the end of his final show), but that would be different but similar to previous regenerations. As to specifically how... RTD said that the 8 year-old viewer is now used to regenerations standing up (with the implication being that that would be how DT would go). "Let’s just say that regeneration is a complicated process, and never as simple as it seems.”
"It wont be the cause of what may occur at the end of the last special but what happened at the end of the Stolen Earth WILL play a big part after his battle with the Master....with regard to what happens next and the difference in this change"
DT: "I think this Doctor likes being this Doctor. He's raging against the dying of the light. And, that's the beat that we play. That's the story. He knows that the sands of time are running out. He's been told. And, the bell is tolling for him, and he doesn't want to go quietly. That's how we play that."
When asked if he was having any steer in Matt's character, RTD said, "Absolutely none. I wouldn’t want to write a single word for him. When he appears, every word will be written by Steven Moffat. He’s Steven’s, and Matt’s, character." As for the regeneration, will there be a dry eye in the house? RTD: "I should f***ing think not!", DT: "Well, I cried (when I read it)." As, apparently, did Murray Gold.
Matt Smith has "a full scene" in "Part Two"."