The two parter by Steven Moffat and produced by BBC America will be a story set in the late 60's as the Doctor, Amy and Rory find themselves summoned to deal with an alien threat. There have been rumours that the story could be based on the Terrence Dicks novel, Blood Harvest but nothing yet has seemed to confirm that theory. Actually from the press releases, it's looking clear that this will be something original, particularly with mentionings of Oval Office as well and possibly that Apollo 10.5 rumour from The Brilliant Book as well.Also returning for this particular story will be River Song, played again by the lovely Alex Kingston and it'll be interesting to see if this will the one that reveals River's full identity or further teases towards it. Either way, this is definitely going to be a different way of opening up a season for the series, proving that Moffat will continue to make his own stamp on the show, regardless of naysayers.
Press Release: http://www.bbc.co.uk/news/entertainment-arts-11510514