"Evacuated to a house in Dorset from war-torn London, Madge Arwell and her two children, Lily and Cyril, are greeted by a madcap caretaker whose mysterious Christmas gift leads them into a magical wintry world." -- iTunes Store
Download for Free!
Written by Steven Moffat and starring Matt Smith as the Doctor, this exciting Prequel shows what was happening to the Time Lord moments before the explosive start of the Christmas Special!
the fine print: Downloads posted on the Free iTunes Downloads blog are usually free for ~1 week. After that, you'll have to pay for them.