Davies: 'Who' Specials Will Have An Arc

Four episodes, that's all the time that's left with David Tennant as the 10th incarnation of BBC's legendary Time Lord before he will regenerate into a newer, younger model in the form of Matt Smith.
However, the final four episodes of Tennant's reign will see The Doctor go head-to-head with all manners of creatures, villains and creepy crawlies.
Despite rumors, the adventure will span four episodes and, although won't exactly be a four-part story, will include an arc that will be the beginning of the end for the 10th Doctor.
"There's the Easter one and then a big gap, and then the other three are going to go out around Christmas time/end of the year," showrunner Russell T. Davies recently told SFX Magazine, courtesy of Sci-Fi Pulse. "It ends in a two-parter. There's a very strong link between the last three specials. It's not a three-parter, but there's a strong connection. As we head towards the ending it gets thematically bigger and bigger.
"Everyone knows that David's going, so you start to write that into it. It's not like a giant spider suddenly turns up and kills him out of the blue! But even in 'Planet of the Spiders' his death was written into it quite properly. So there's a feel of that to it. Everyone knows where the story is heading, especially with Matt Smith being everywhere. It's nice actually. We play with that."
However, what could be one of the most surprising revelations is the fact that Davies, who resurrected the series in 2005 and saw not one but two Doctors live and die, has always known how this Doctor would die. In the later half of the 2009 specials, The Doctor will once again encounter the Ood (the squidish creatures with a prophecy for The Doctor) and his song will finally end.
"The details have changed - who's, where, and the geography of it. But yes, I always knew," he said. "There's only one way to do it, really. It's there in my head. If I could just put a wire into my head it would be on the paper now. Literally, stage direction by stage direction I know what happens. I think it's going to be a brilliant piece of television."
With the news on who will be taking over the legendary character now very much in the public domain, there has been widespread speculation on how Tennant's character will "die" and regenerate into a new Doctor and how Smith will make his debut on the series. Davies certainly isn't about to give away his deepest secrets, however he shows a lot of enthusiasm for Smith's first episode which has already been penned by new showrunner Steve Moffatt. And Davies is promising an epic adventure to break in the new Doctor.
"Mine will end and his will start" with the regeneration, Davies said about the changing of the guard. "And his is a big, bold, brand new start, and it very much powers under its own steam. It's simple, really. There's a new man and off we go."
"Doctor Who" returns on Easter for "Planet of the Dead."