Roots: Silent Night, While Shepherds Watched Their Flocks By Night. The Night Before Christmas (Blitzen as the fish's name refers to the reindeer as much as its nature), Carry On Screaming ("frying tonight!"). The Doctor's musical TARDIS key ring plays We Wish You a Merry Christmas.
Intertextuality: The adventure Susan and her grandfather the First Doctor shared on the planet Quinnis (see: Links) was told in Marc Platt's Companion Chronicle Quinnis.
Dialogue Triumphs: "Strewth, everywhere you turn, it's always Daleks smashing things up."
"Pudding's the last thing I want!"
Continuity: Fledershrews are bat-like creatures which live in the TARDIS, having adopted it as their new home, On their home world they are endangered, and the Doctor (presumably the Seventh?) rescued them. Lucie says she never noticed them "before" (probably not around the bedrooms), though knows there were more of them around previously.
The dried airfish, or Blitzenfish is native to the Aurora Gloriosa region. Also called the Resurrection Fish it can lay dormant for years, growing to up to 14 metres in length. In its carapace it carries a harmful electric charge for hunting and self-defence - it also is heavily finned and spiny like a lionfish. The specimen bought from a bridge market on Quinnis by the Doctor for Susan was originally smaller (being dried) and was attractive to her for its colours. Blitzenfish leap about in space and time to hunt, but in doing so inside the TARDIS threatens to destabilise its interior
Earth is beginning to pull itself together, according to Susan, and was as recently as one month ago visited by an Iborean trader ship, most likely prompted by the Doctor.
The TARDIS' fault locator is, once again, on the blink (see: Links). It is equipped with full insulation suits. The TARDIS corridors are lit by a natural phosphorescence. On an upper deck the Doctor has a holding ring comprising the un-jettisoned rooms of his previous companions, including Susan's, which he established after she left (see: Links) "-just in case". Named companion rooms include Ian, Barbara, Vicki, Steven, Dodo, Ben, Polly, Victoria, Jamie and Tamsin (the most recent). The Doctor deletes all of them, save one. The Ship's powerhouse is located on a floor under the Console Room, and can be accessed via a trapdoor. In the TARDIS Library is a dusty copy of Bortmurt's Bestiary of the Fourth Dimension, including entries on Blight Strawberry, Blinny Clusterdabs, Blisterbeetles and Blithewings
Alex is not telepathic and has only seven per cent Gallifreyan gene stock and one heart. He has been told stories of his mother's and great-grandfathers adventures. He is studying architecture at University.
Lucie is not fond of sprouts. She is aware of the Time-Space Visualiser.
The Doctor's undrawn UNIT salary enables him to draw down a considerable amount of money (after interest) with a debit card.
Q.v. 'Temporal Grace'
Links: An Earthly Child and The Daleks (mention made of the Dalek City, fluid links and Alydon's cloak), The Chase (The Time-Space Visualiser) The Dalek Invasion of Earth as well as Death in Blackpool. Lucie's Aunty Pat is mentioned. The Aztecs, The Book of Kells. Paper Cuts (Draconian sazou pieces). Fledershrews were first named in Nevermore, though they may be the flying creatures seen in the Cloister Room in the TV Movie. The TARDIS' fault locator switch was itself famously at fault in The Edge of Destruction, which is also where the planet Quinnis is first mentioned. Susan mentions the Blinovitch Limitation Effect. Lucie mentions Daleks (Blood of the Daleks)
Untelevised Adventures: It is hinted that at a prior point the Doctor and Lucie collected a Norwegian spruce tree (roots and all) for the TARDIS, with the intention of replacing it once Christmas is over. The Doctor and Susan reminisce about the planet Ambrosia, where everything smelled of spice except for its sovereign (hence her title of prestige). On the moon beach of Thalassa (presumably the Neptunian satellite) she collected shells. The Doctor, while travelling alone, visited 'old Leonardo' Da Vinci and took him to Bethlehem using Roman census records to get the exact time and place to witness the first Christmas, so the artist could study the light for his Adorations. Spooked by the imminent even, Leonardo bottled out, opting to complete the work from his own imagination.
The Bottom Line: 'Sometimes the future is unavoidable'
Platt's family reunion, take two. A Christmas setting makes this all the difference, with a tale of looped time, locked rooms and letting go. It's the nicest Christmas Lucie can hope for, and, as the Doctor promises, a vast improvement on last year's. Lovely music, too.