It's a ten minute walk down to the station halt at most, but since quarter to four Delia's had her shoes on and has been stood at the window, alternating her gaze between the flakes of snow drifting down and her father. That morning, Delia had mentioned wanting to go to meet Patsy on her own, but – much stronger though she is – Mrs Busby doesn't want her wandering around on her own after dark, so has insisted that David (and, inevitably then, the dog too) walk down with her. Mrs Busby's glad she put her foot down on this: if she hadn't, Delia would be out there on her own on the cold exposed platform now.

Finally, at ten past four David relents and agrees that they can set off. Mrs Busby waves them off, then with the pair of them out of the way, has a quick tidy up, anxious about what their visitor will make of their little, provincial home and keen to make a good impression.

At quarter to five Mrs Busby pops into the kitchen to put the kettle on; just in time too, for a few moments later, there's a clatter of noise at the front door, and David and Delia (and the dog) are back with their guest.

Once hats and coats are off, and Patsy's suitcase is deposited at the bottom of the stairs, they sit down to tea. Patsy seems a bit stiff, a bit formal – a bit nervous, even - to start with, but as she warms up (in more ways than one) over the tea she regales them with tales of Nonnatus in the days since Mrs Busby and Delia left London. Patsy seems to have had an eventful time: she recounts how she'd taken the cubs (with Father Christmas – 'not the real one,') to see the lights on Oxford Street and how one of them had been violently sick after eating too many of the sweets that Tom the vicar had handed out; how the Christmas play had had to be cancelled because of a measles outbreak; and most alarmingly, how Sister Monica Joan had gone missing for days, and had only just been tracked down somewhere in the middle of Berkshire by Sister Evangelina.

Delia listens with wide-eyed wonder, but Mrs Busby supposes that the expression on her own face isn't too far different. So much seems to have happened in London in just a few weeks that she's exhausted just thinking of it.

Patsy also tells them how, that very afternoon, all her colleagues at Nonnatus are performing in their makeshift choir for the BBC.

'The BBC!' David is impressed. 'You could've been on the television and instead you've come all the way out here to snowy Wales. Imagine, us knowing someone on the television! We could've been watching you on Christmas day.'

Delia, though, is less impressed with the idea. 'We don't have a television.' She looks sourly at her father: Mrs Busby guesses that the thought that Patsy might have stayed away in order to be filmed by the BBC is one that doesn't sit well with her.

Patsy waves a hand. 'I can't really sing. And, besides, I'd already made plans.' Her gaze falls on Delia for a moment, then shyly, slips away to land somewhere on the carpet.

'Still, it's a shame,' David continues. 'A once in a life time opportunity.'

But if Mrs Busby judges right, he's the only one in the room who's entertaining anything like regret that Patsy's not singing with the rest of the Nonnatus choir that afternoon hundreds of miles away in London.

'Come on Pats,' Delia says then, clambering to her feet. 'Let's get your bags upstairs. I'll show you my room.'

'Delia,' Mrs Busby calls up the stairs. 'Delia! We'll be late if you don't get a move on!'

For the last half an hour there's been a murmur of chatter and laughter floating down the stairs, and Mrs Busby has resolved to leave them to it as long as she can. But they have to be at the village hall by six thirty, and they'll miss the start of the carol service if they don't set off now.

'Sorry Mam,' Delia calls down the stairs, as she and Patsy emerge from her room.

'Is that the only coat you've got, Patsy love?' Mrs Busby tuts fretfully at what Patsy's wearing as she comes down the stairs: her coat might be suitable for the weather in London but it looks a bit thin for the Welsh night air. 'Hang on a minute, I'll lend you one of mine.'

Delia protests. 'She can't wear one of your coats, Mam!'

'What's wrong with my coats?'

'It'd look – well – Patsy's taller than you are, for a start.'

'It's very generous of you, Mrs Busby,' Patsy attempts to be the peace maker, but Delia's having none of it. After a couple of minutes' standoff, they compromise by forcing Patsy into an extra jumper and a woolly hat.

As Mrs Busby's locking the front door, Delia and Patsy are already at the end of the path and away down the lane. As soon as she could, Delia has linked arms with Patsy, ostensibly to guide her on her way, but clearly with another intention in mind.

It's one of those things that Mrs Busby thinks she'll choose not to notice. In the dark and with the snow coming down as it is, it's hard to see that far ahead anyway.

Later, after they've made it back home from the carol service in the village hall, and are sat round the fire roasting chestnuts, the Busbys reminisce about Christmases past, and Delia shows off to Patsy some of the things she can remember.

'What about you, Patsy?' Mrs Busby asks in a lull in their remembering, not wanting her to feel left out. 'What do your family usually do at Christmas?'

Suddenly pensive, Patsy stares into the fire. 'It's a long time since I've had a family Christmas,' she says quietly. After a moment she looks up, attempting brightness. 'I lived in Singapore as a child – I didn't see snow until I was fourteen.'

'Are your parents in England now?'

Patsy shakes her head. 'My father is,' she says, staring into the fire again. There's something there, some secret, some sorrow, that Mrs Busby has inadvertently stumbled into, and she kicks herself for having done so, and wonders how to make amends.

But Delia seems to know what to do. She reaches out to Patsy, covers her hands with her own and tries to catch Patsy's eye. After a couple of minutes, Patsy looks up at Delia, and smiles.

The next morning, Mrs Busby's up early to get the turkey in the oven. She's just making pastry for mince pies when Delia and Patsy, both of them still in their pyjamas, stumble into the kitchen. Delia fusses with the kettle.

'Do we not have any coffee, mam?' she asks, rummaging in the cupboard.

The question startles Mrs Busby slightly. Delia hasn't asked for coffee before, and it's not something they usually have in the house, since neither she nor David usually drink it. It must be something else she's remembered: exotic London tastes, no doubt.

'Sorry love,' she says. 'You'll have to make do with tea.'

'Wait here,' Patsy says, and disappears upstairs. She returns a minute or so later with a neatly gift-wrapped parcel.

'Presents aren't till after Christmas dinner, Pats,' Delia says. 'It's tradition.'

That's another thing Delia seems to have remembered. But remembering doesn't seem to have made her any more patient than she's ever been. 'What time's dinner, Mam?' she grins.

'Open this one now,' Patsy says, holding it out to her.

Delia takes it from her, and as she's always done, tries to guess what it is before she opens the paper. She weighs it, rattles it, squashes the paper down to reveal its outline. Then she sniffs it. 'Pats!' she says, delighted. 'How did you know?' She rips open the paper to reveal a packet of coffee.

Patsy shrugs, smiling a little bashfully. 'Lucky guess, I suppose.'

A couple of hours later, after Delia and Patsy have drunk their coffee, eaten a spot of breakfast and got dressed, they're in the kitchen with Mrs Busby making their way with more enthusiasm than efficiency through the vegetables that need peeling. Mrs Busby thinks she'd probably get the job done quicker – and with less waste – without them there, but it's nice to have company, to have the pair of them in there with her, chattering, teasing each other, and singing along to the radio.

'Mrs Lloyd's sow'll be getting a good meal the way you two are going at those veg,' Mrs Busby says, looking across the kitchen. The waste pile is a mountain of thick vegetable peelings.

'What goes around comes around,' Delia grins, gesturing towards the sausages and bacon that Mrs Busby is assembling into pigs in blankets.

'I hope you're a bit more gentle with your patients than you are with those parsnips! I'm surprised there's any of them left.'

'Any patients or any parsnips?' Delia waves the offending (offended?) root vegetable at her mother.

'Both!'

'I'm happy to admit I'm not one for kitchen duties,' Patsy cheerfully admits. 'I can't cook. I've never had to, really.'

'Nor can Delia,' Mrs Busby teases. 'She can burn water.'

'Mother!' Delia is outraged.

'What on earth were you going to do about cooking once you got into the flat?' Mrs Busby asks Patsy.

'I don't think we'd really thought about that,' Patsy grins. 'Live off biscuits, perhaps. Or starve.'

Mrs Busby laughs.

'What flat?' Delia asks. Mrs Busby and Patsy stop laughing, suddenly. Somehow, in their high spirits, they've forgotten that neither of them have spoken – not explicitly, anyway – about the flat in front of Delia.

Mrs Busby looks at her daughter, and feels a peculiar prickling on her skin. Delia's got that look that's been coming more frequently these days, like she already half-knows the answer, like she's caught hold of the outline of a memory and she's lifting it up to the light to see its details.

'Pats, what flat?' Delia asks again, in a quiet, urgent voice.

Patsy turns to her, gently. 'Before the accident,' she explains, 'you and I were going to move into a flat together.'

'I thought –' Delia says and stops. She thinks for a moment. Then, 'We hadn't moved in,' she says, with conviction.

'No, we hadn't,' Patsy says.

'We had no furniture.'

'No, we didn't,' Patsy agrees.

'But we'd got the key, and we went there to have a picnic and we – ' Delia stops and seems to catch her breath, her eyes opening wide. A half-smile starts to play about her lips. She looks up at Patsy with a look of wonderment.

'Mm,' Patsy says, with her own answering half-grin. She's flushing a little – no doubt, Mrs Busby thinks, made awkward and embarrassed by Delia remembering their plans to live together in front of her.

'And after, I was late for work,' Delia says.

'And then you borrowed my bike,' Patsy replies.

'Oh,' Delia says. 'And that was when – ' she points to her head.

'Yes. That was when,' Patsy confirms.

Delia exhales, blinks. Swears. 'Bloody hell.'

'Delia. Language!' Mrs Busby says automatically.

Delia's rubbing her forehead: she has a look that suggests certain things are falling into place. A mix of emotions seem to flit across her face. She's staring at Patsy with a curious kind of intensity.

Mrs Busby turns away: she wraps up the newspaper of veg peelings and takes them into the scullery to the slops bucket.

When she returns, Delia says, 'Mam, do you need us to do any more?'

Mrs Busby surveys the kitchen. There are piles of veg in tins ready to go into the oven to be roasted; there's a small mountain of sprouts peeled and ready to be popped in a pan ('Do I like sprouts?' Delia had asked the day before. 'Yes,' Mrs Busby had replied, not entirely telling the truth. 'Mam, are you sure?'); the pigs wrapped in blankets are snug in their tray. She just needs to wait for the turkey to come out of the oven so the veg can take its place, and then there'll be the gravy and a few last things.

'No,' Mrs Busby says. 'I think we're about done.' There's the table to set, but David always does that (it's tradition: Christmas is the one time a year he does the table, and the one time a year he does the washing up too).

'Do you mind if we – I think Patsy and I need to talk,' Delia says, in a voice that's suddenly very serious.

Patsy nods, looking a little terrified, if Mrs Busby can read the expression in her eyes.

'Shall we –' Delia points outside.

'A breath of fresh air'll do you good before your dinner,' Mrs Busby says, as if to convince them all that all they're doing is going for an invigorating preprandial stroll, rather than – well – rather than whatever they're going out to talk about.

In a curious silence, the girls put on their hats and coats and head outside.

David comes in (the dog at his heels) just as the back door has closed behind them. 'Where are they off to?' He asks.

'They've just popped out for a bit of air before dinner,' she says.

'And they haven't taken the dog?' he bends over and fusses over the dog. 'Poor old dear,' he says.

'Will you set the table, love?' Mrs Busby says, watching out of the kitchen window as Delia and Patsy head out into the lane beyond the house.

And that's when she realizes she's going to have to break one of the promises she's made to herself. She'd decided, the day before, that she won't go into Delia's room while Patsy's here: she refuses to risk knowing if people aren't sleeping in the beds that they ought to be sleeping in. But the Christmas table cloth is in the cupboard in Delia's room. She'd been meaning to ask Delia to get it, but now she's gone out she can't; and it'll be too late by the time she comes back from wherever she's gone with Patsy.

There's nothing for it. She'll have to go in.

After hovering on the landing for a moment, she pushes open the door. She sighs at what she sees. She might have known it: both beds are made up immaculately, giving no clue to who slept or didn't sleep where. One of the consequences of them both being nurses, no doubt; between them, they've probably made up thousands upon thousands of beds in their time.

She doesn't linger too long in there, anyway. She gets the table cloth out of the cupboard and goes back down stairs to check on the turkey.

An hour or so later the girls are back, the brisk winter air having put a glow in their cheeks and a shining brightness in their eyes.

After dinner they retire to the sitting room (still wearing their paper hats) and it's finally time for presents.

(What to get Patsy had posed Mrs Busby something of a problem; a couple of weeks earlier she and Delia had headed into the local town one afternoon to go shopping. In the fourth shop they'd been in, Delia had chosen something for Patsy – a bold chunky bracelet, polished so it reflected the light.

'Are you sure?' Mrs Busby had said. 'It's a bit – modern,'

'She'll like it,' Delia had replied with absolute certainty.

Mrs Busby, meanwhile, had ummed and aahed, having nothing like the same clarity her daughter had. Finally, in the haberdashers to pick up some buttons for David's shirts, she had thrown her hands up in despair.

'A scarf,' she had said, decisively. 'You can't go wrong with a scarf.'

Delia had supervised the choice of wool: 'Something green, I think. That'll look nice with her colouring.')

Patsy's delighted with the presents, it turns out, and what she has to offer goes down well too. Mrs Busby unwraps an artfully decorated box in which are three jars: two containing Mrs B's chutney (highly recommended) and one containing Sister Winifred and Sister Monica Joan's mincemeat (highly flammable). David is pleased to unwrap a bottle of scotch from Patsy.

When Delia wants her present from Patsy, Patsy shakes her head. 'You've already had yours,' she teases, grinning at Delia. Delia grins back.

'Oh, the coffee,' Mrs Busby says, remembering that morning.

Delia looks at her, confused for a moment. Then she remembers. 'Oh yes, the coffee. You've got me something else, though, haven't you Pats?'

Patsy has got Delia something else (she probably spoils Delia sometimes, Mrs Busby thinks): after the usual show of trying to guess what the presents are through the paper, she unwraps a silver photo frame and a book.

'It's something you had been talking about wanting to read for a while,' Patsy tells Delia as she tears the wrapping from the novel. 'I think you'll still like it.'

Mrs Busby picks it up to have a look: she's never heard of the author, someone called Claire Morgan, but Patsy seems to know what Delia's tastes are, so she supposes Delia will enjoy it.

For the moment, though, Delia's more interested in the photo frame. David's had his camera out over Christmas dinner, and now Delia says, 'I'm going to put a photo from this Christmas in it. Dad, set the timer on that thing. I want one of all of us.'

As she's standing beside Patsy and her daughter while David arranges the camera on its stand, she notices something: the thread of a gold chain around Delia's neck. She's about to reach over, to pull it out for a closer look when she thinks she recognizes it. She can't see what's attached to the chain, but she's fairly sure she can guess what's making that faint, circular outline on Delia's collar bone, underneath her jumper.

Now she's seen it, she can't pretend she hasn't. She tries to remember if she's seen Delia wearing it before today: she doesn't think she has. Is that what they were doing this morning, then, she wonders? Was that one of Patsy's presents for Delia?

'Smile', David says, rushing over from the camera with more speed than elegance.

She hesitates for a moment, and then she does. They all do.

They've just finished posing when there's a knock on the front door, and without waiting for a reply, her sister and her husband, her niece and her husband, and her great nephew and great niece all pile in, throwing 'Merry Christmases' around the room, dispensing hugs to everyone they bump into, and turning up the ambient noise in the room into something deafening.

The next two hours is lost in boisterous noise: after twenty minutes, for a bit of peace and quiet - and in an act of generous hospitality - Mrs Busby retreats into the kitchen to knock up some mince pies with the Nonnatus mincemeat. Patsy was right in her characterization of the mincemeat, she thinks as she opens the jar: there's enough brandy in it to fell a horse.

In amongst the noise from the sitting room, she catches fragments of conversation.

'So, Delia, cariad, when are you going to settle down and get married?' she hears her sister ask. She winces. It's a question she used to ask of Delia herself, pretending not to see the wounded look that Delia would get as she would try to convince her that a career was more important to her than any romantic involvement. It's a question Mrs Busby has long since found ways to deflect, on Delia's behalf, whenever someone like Gwynneth asked it.

'You don't want to be an old maid,' she can hear Jane, her niece, piling on the pressure.

'Now then,' someone else interjects – it sounds like Daffydd, Jane's husband. 'She's been ill, she's recuperating. There's plenty of time for getting wed when she's well again.'

'She gets up to all sorts in London, I'm sure,' Jane says now.

'Do you have a chap, then, Patsy?' Gwynneth's turned her attention from Delia. Or rather, Mrs Busby thinks, she's trying a new angle of attack.

'Never really seen the point,' Patsy says.

There's a rather chilly note in Patsy's voice, Mrs Busby thinks. She goes to intervene, sticking her head around the door and asking, 'Now, who wants tea?'

When she's back in the kitchen, she bangs about the cups and saucers. She's cross with them all.

'She's a bit posh, isn't she, your Delia's friend?'

Gwynneth's followed her into the kitchen. She chooses to ignore the weight Gwynneth places on the word 'friend': she knows exactly what she's aiming at, and no matter how accurate Gwynneth happens to be in her assessment of the situation, she won't give her the pleasure of knowing that.

'Oh, Patsy's alright,' she says.

Gwynneth's always been niggling at her about the choices Delia's made. Everything Delia's ever achieved – when she got her school certificate, when she went away to nursing college in London, when she qualified, when she got her first appointment and her first promotion – her sister has tried to belittle. Gwynneth has always hit back, talked over her with tales of her own children, none of whom have run off to London, all of whom have married and set up home within spitting distance of the village, all of whom have produced grandchildren.

The thing Delia has now is not ideal, in many ways, Mrs Busby reflects, but she wonders if it's actually the best thing given her daughter's determination to have a career. Delia couldn't keep up her job in the same way if she married; at least if she's with Patsy, she'll get to work and have the love and comfort Mrs Busby has always wanted for her.

The only thing is, Mrs Busby thinks, it's a shame about the grandkids. Delia's got a nice way with children; Patsy too, going off her ability to calm Jane's two down and to get them to play nicely.

The dog comes into the kitchen, sniffs around her ankles. Mrs Busby grins. Well, they could still get a dog, at least. The grin falls. Patsy had confessed, the day before, to not being a dog person. Mrs Busby sighs. Maybe a cat instead, then.

After a couple of hours, having decided they've made enough noise in the Busby house, Jane and Daffydd decide to take the kids home; Gwynneth and John take their leave too. Delia and Patsy go with them part of the way to give the dog her evening walk, and silence descends on the house once more.

Well, more or less: David's stretched out on the settee, dozing gently in front of the fire, and snoring every now and then.

Mrs Busby picks up the book Patsy bought Delia to have a look at it while the house is quiet.

After twenty minutes or so, the girls are back.

'Tea?' Mrs Busby puts down the book and asks, when they've taken off their outdoor things and are back in the sitting room.

'Let me,' Patsy offers.

'No, Patsy love. You stay in here and get warm.'

Mrs Busby bustles in the kitchen. After a few minutes' work she's done: on one tray, she's put a pot of tea, cups, saucers, milk, sugar, and mince pies (made with the Nonnatus mincemeat); on another, she's put turkey sandwiches, the two jars of Mrs B's chutney, four plates, a couple of knives, and the salt and pepper.

She carries the first tray in.

David's still sprawled on the settee, asleep. Patsy's sitting in the armchair, with the newspaper on her lap, reading out the clues from the crossword. Delia's sitting on the floor at her feet, resting her head against Patsy's knee. The dog is stretched out next to her, her head in turn resting against Delia's knee.

Mrs Busby tuts. 'Delia, surely you're not comfortable on the floor.'

'I am, though. And besides, I can't disturb the dog.' Delia grins up at her mother.

'Well, at least get a cushion to sit on.' She leaves them to it, and goes to get the second tray. Patsy'll be gone by tomorrow lunchtime, back to her heavy caseload in London, so she lets them make the most of it while they can.

Delia will be going to London too, soon enough, she knows. She's getting better, stronger, every day, and her memories are coming back. She still has headaches now and again, but nothing like those she had at the start.

What was it she'd said to Patsy that day in the park? That she wouldn't change Delia. She wouldn't. She wouldn't change Delia for the world. But when Delia goes back to London, she wouldn't mind seeing a bit more of her than she has done in the last ten years.

When she waves Patsy off tomorrow, then, she won't say 'Come again next year.' But she knows, when the time is right, she'll make the invitation. They might not come next year: they might be working, they might not be able to get away. But she'll still ask. She'll make sure that Delia knows they are both welcome. When the time comes, she'll make the invitation, and this time she won't regret it.

THE END. (Really, this time)

Thanks for reading, and especial thanks to those of you who've reviewed this – it makes all the difference to know that people appreciate it!

Happy New Year to you all!