So, how does The Doctor repay the kindness of the woman who helped him find the TARDIS after he'd survived a plunge to Earth out of the upper atmosphere in 1938? He returns three years later and puts her, and her two children, into mortal peril!
Oh, Doctor, when will you ever learn? Sometimes a "thank you" card will suffice.
It's Christmas Eve, 1941, and Madge Arwell (Outnumbered's Claire Skinner) has learned that her bomber-pilot husband Reg (Alexander Armstrong, the voice of 'Mr Smith' in the Sarah Jane Adventures) has been lost over the English Channel returning from a mission.
Determined to give her children, Lily (Holly Earl) and Cyril (Maurice Cole), the "best Christmas ever" - before breaking the news about their father's death - she relocates the family to their uncle's old house in Dorset.
However, instead of the usual caretaker (who presumably had a sudden win on "the lottery"), there they find a particularly manic Doctor - masquerading as The Caretaker - doing a very impressive Mary Poppins impression with animated furniture, sink taps that produce lemonade, bedrooms full of childish delights etc
His main present though is a gift-wrapped box that contains a dimensional portal to a snow-cloaked, Narnia-esque world of 'living' Christmas trees that spontaneously grow ornaments (the trees' seeds).
Unfortunately, the "safest place in the universe" has been targeted by futuristic strip miners - who just happen to arrive at exactly the same time as The Doctor and the children - looking to melt down the forest (with acid rain) and convert it into precious fuel.
The Doctor, The Widow And The Wardrobe is typical Steven Moffat Christmas fare, a convoluted tale told at break-neck speed that builds to a suitably, seasonally, upbeat ending.
There is, unsurprisingly, much too much going on throughout - with the cameos from Bill Bailey and Arabella Weir as the Douglas Adams-lite 'lumberjacks' from the future being almost pointless - and several of the set-pieces (such as Madge piloting the giant mecha robot) border on the absurd. In fact, the characters from the 1940s are remarkably okay with the whole idea of time and dimension travel and seem pretty much unphased by most of what happens to them.
But as is often Moffat's way, the plot barrels on regardless, steamrollering over any WTF moments or plot holes, to get to its happy ending for Madge and the children, followed by a surprising sweet ending for The Doctor as well.
For me, the story didn't really come into its own until The Doctor and the children were trapped inside the lighthouse made of trees. Up until then, I'd found the velocity of events slightly heavy-handed and the 'manic' Doctor (when he first appeared as The Caretaker) was actually rather irritating and certainly not the charming, bumbling Doctor I usually enjoyed watching.
There was also an inescapable whiff of Moffat going for the soundbites that would make for good trailer material, definitely playing up the similarities to The Lion, The Witch And The Wardrobe that the title suggested, but really weren't there beyond the visuals of a snowy land reached through a "magical portal" and explored by children in 1940's dressing gowns!
It's quite telling though that the episode didn't end with a "next time..." or "The Doctor will return in..." because, of course, now fans have the long wait until Autumn 2012 for the next season of Doctor Who to begin.