In an article with Doctor Who Magazine, Doctor Who showrunner Steven Moffat revealed that:
"There will be a huge cliffhanger... that we wouldn't normally do at the end of a series of Doctor Who because it would be too long before it came back. [It is] an enormous, game-changing cliffhanger for the Doctor, Amy and Rory. It will change everything for them."He also promised that there will be revelations involving the Doctor's friendship with Amy Pond in upcoming episodes.
Moffat also teased that:
"You will see the Doctor's life change forever, you will gasp in astonishment at the true nature of his relationship with Amy and you will cry out in horror as Rory Williams stumbles to the brink of a tragic mistake."Doctor Who is set to return to BBC One this Christmas.
[Via Digital Spy]