Our next scene of a Doctorless universe is Donna having a shouting fit over having been sacked.  It's a great scene until her boss explains that he's losing business because the Thames is still "closed off" after having been drained a few months ago at Christmas.  Strike One, logic.  Exactly how long is that thing going to be dry, considering that it partially gets tides from the Atlantic?  And moreover, why does it need to be "closed" when the businesses presumably are shipping goods via the bridges, for which it makes no difference whether the riverbed below them is dry or not?  Donna, unphased by this plot flaw, is still raging at the realization that she is not just sacked, but has been replaced.  She storms around the office, claiming supplies as her own property and slagging off her officemates while the rest of the office stares in horror at the news reports from the missing Royal Hope hospital.  

"Have some respect! There are 2000 people in that hospital, and it's vanished!" her boss spits.  Donna doesn't care, outing an office thief as she marches out.  There's an earthquake and she triumphantly announces "Don't tell me - the hospital's back!"  

It is, and Donna, Wilf, and Sylvia are watching the report of the sole survivor, Oliver Morganstern, who talks about the nobility of his colleague Martha, who gave him the last oxygen tanks and smothered in front of him.  Wilf insists that the space rhinos must be aliens.  Sylvia, supremely uninterested, is combing through Donna's box from the office, making dry comments about the hole punch, the raffle ticket, and the stapler with Donna's replacement's name on it. Only Wilf is agitatedly pointing out that there is an increase of alien activity in a line that is almost-but-not-quite a quote from War of the Worlds.

Donna doesn't believe in aliens, but she is pleased that her mother isn't insane with fury about her being sacked.  "To be honest, I've given up on you," Sylvia says.  (Strike Two, Sylvia. Only a jerk would blame anyone for being downsized due to business problems, and that phrasing takes her issues with her daughter into psychotic bitch territory.)

Donna chews on that while Oliver delivers a memorial for Sarah Jane Smith, who had tried to take the Doctor and Martha's place in Royal Hope Hospital.  Instead, she and the entire Sarah Jane Scooby Gang died in the attempt.

Walking out for chips for dinner, Donna runs into Rose again - or almost the other way around; there's a flash of light from an alley and Rose scuttles into the road, almost falling over.  Donna goes to help her, and Rose cheerfully asks how things are while she stares unnervingly over Donna's shoulder.  Randomly, Rose asks what her Christmas plans are, suggests that she takes takes a vacation out of town, and when Donna protests that she can't afford it, points out that the raffle ticket will be a first prize vacation winner.

Donna freaks out and tells Rose to leave her alone, never looking back as lights flash and Rose vanishes again.  But she's not too proud to take the vacation, for the next scene is the Noble family driving up to one of the Whoniverse's go-to location sets.  Conveniently for the Nobles, the alzheimers patients, the Sontarans, the alien-worshipping nuns, and the various other baddies from the SJA, Torchwood, and previous episodes of Who have been cleared out, and at first the worst thing to be seen is the pinched expression on Sylvia's face. She's horrified that they're only there because they're raffle winners, and doubly horrified that Wilf, never shy to have a good time, is wearing not one, but two, sets of plush antler headbands.

Christmas Day brings a Hispanic maid delivering breakfast and Spanish warnings about a spider, and for a moment Donna sees legs on her back - but she's rapidly distracted her mother calling her to the TV to watch the Titanic fall on top of Buckingham Palace.  A moment later, the whole building shakes, and they run outside to see a mushroom cloud rising from London.  In this alternate universe, the city had not emptied itself due to the nonsense from the previous two Christmas specials, so the Nobles watch everything and everyone they knew literally go up in smoke while the maid - apparently the only domestic in the entire hotel - gives Donna the evil eye.

The good news is the impact did not, as the Doctor predicted in "Voyage of the Damned," crack the entire planet open.  The bad news is that it did irradiate the entire south of England, and France (probably also partially glowing in the dark) has closed its borders to refugees. (No word on Ireland, which should have some room to spare.) We next see the Nobles three months later; they've been living in a homeless shelter and are now being shipped - over Donna's protests - to a home in Leeds.  While Donna talks about getting work and Sylvia fantasizes about having a washing machine, they are shipped via military transport to their "billet" in a row house that turns out to be packed to the gills with a generic extended Mediterranean family.  They're implied to be Italian, but their only member with speaking lines is playing Zorba the Greek.

The Nobles get to sleep in the kitchen.  Wilf is the only one attempting to put any kind of a positive spin on it, saying they can show a little of that "wartime spirit" ("But there's no fight!" Donna protests) and besides, America has promised 50 billion of pounds in funding. "God bless America!" Wilf announces, a rather unexpected sentiment to hear on British TV.

It's nice to hear, but the next thing the Nobles are hearing is the news that America is in crisis, roughly a fifth of the population having dissolved into adipose.  There's a certain faint triumph about the loss of all those fat people in the tone of the emaciatedly skinny news announcer.