The sounds of the motor haven't even faded away before their daughter flies up the stairs like a shot, leaving her parents to glance at each other, worried.

"What on earth was that?" Matthew asks in a low voice. Mary frowns.

"I'm not sure," she says slowly. "Didn't you think David was behaving oddly at dinner?" Matthew snorts.

"Other than announcing his intentions to marry the as yet unheard of Miss Vandergeln?" he asks bitingly. "Despite having lavished his affections on our daughter for - my God, I feel old - seven years now?" Mary fiddles with her gloves, her eyes flicking to the ceiling.

"He was going to propose to her, I know it - his mother all but told me at tea Thursday," she murmurs as somewhere in the house a door slams. "She's not telling us something." Her husband makes a face.

"It's not in her nature to be secretive," he says, but Mary is already shaking her head.

"It's in every girl's nature to be secretive," she replies with a sigh. "Why don't you go talk to her?" Matthew stares at her, incredulous.

"Me?" he asks, eyebrows raised. "This is out of my jurisdiction, darling. You handle Isabella - I shall shoot the boy." She sighs again; her husband is joking, she knows, but only just. They have known David and his family for years - years and years - but Isabella is without a doubt Matthew's little girl through and through. Anyone who dares hurt her in any way has the Earl of Grantham's wrath to face, and she does not envy the Rory boy right now, not at all.

"All right, then, send for your musket," she says wearily, heading for the stairs. "But you know she won't listen to me. She never does."

She really doesn't, Mary muses as she makes her way to her daughter's room. Of all their children, Isabella resembles her father the most, and she makes it clear she prefers his presence to hers. In temperament and coloring alike, they mirror each other: she has his beautiful blue eyes and his stubbornness, his sloping nose and his unwavering loyalty. She is Matthew's little girl, through and through, and never needs her Mamma. Hugh, Edie, even the coolly aloof twelve-year-old, Robert - all of them, at one time or another, have chosen Mary as the protector, the nurturer. But even as a baby Isabella quieted only in her father's arms, while when Mary held her, she would stare up at her in a kind of polite confusion.

And, to be fair, Mary doesn't understand her either. Her daughter rides bicycles, not horses; she loathes new clothing and talks only of Egypt and India - far off places that Mary had never given a second thought to when she was Isabella's age. Downton was her world, will always be her world - Isabella's dissatisfaction with it only serves to widen the gap between mother and daughter. Isabella is a stranger to her, a beloved one, but a stranger nonetheless.

"Give her time," Matthew says incessantly. "She's only eighteen."

Only eighteen. There was no "only eighteen" when Mary was eighteen - there was duty and responsibility and dignity. Now - nothing but jazz and independence.

She softens somewhat as she nears her daughter's room; the unmistakable sound of someone attempting to stop crying and failing miserably trickles into the hallway. She gives her daughter a few minutes, wincing with each gulp, but eventually can linger at the threshold no more. She knocks, pauses, then enters.

Isabella's back is to her, rigid and defiant.

"Go away," she says thickly. Mary sighs, but makes no reply, instead picking up the silver hairbrush on the night table. Her daughter doesn't move as she gently pulls the pins out of her hair, letting the blonde waves settle about her shoulders.

"Now," she says firmly, sitting down next to her. Isabella immediately readjusts so that her back is to her mother again. "Talk."

"Whatever do you mean?" Isabella asks haughtily and Mary has to bite back an unexpected laugh - how like Granny she sounds.

"You know precisely what I mean," she chides, hiding a smile. Her daughter remains obstinately mute. "Mr. Rory seemed distracted tonight," Mary prompts and Isabella coughs.

"I'm sure Miss Vandergeln must occupy his thoughts, given their recent betrothal," she replies acerbically, but ruins the effect with a wet sniffle. "How - how happy I am for him." Mary pulls the brush through her hair, waiting.

"Very sudden," she comments, watching her daughter's shoulders straighten.

"Very," she agrees tightly.

"Isabella, darling," Mary begins, but without warning her daughter flings herself into her pillows, crying for all she's worth. Mary sets the brush aside, rubbing circles along her daughter's heaving back.

"P - please go away," she sobs. "I don't want to talk right now." Her mother ignores her, thoughtful.

"You know, your father proposed to me twice," she ventures after letting Isabella get the worst of it out of her system. Isabella does not surface from her desolation, but she doesn't dismiss her either. Slightly encouraged, Mary continues. "I waited too long the first time and he retracted it. Then the war started, and the next thing I knew, his engagement to a Miss Lavinia Swire was announced." Isabella burrows her head further into the bedding.

"This is not helping at all," she says crossly, but she shifts her head so that Mary can see a bit of her daughter's face, red and splotchy and wet, but curious.

"I became engaged, too," Mary goes on, carefully. "To a man who was very powerful and very rich and very different from your father. I convinced myself it was better that way. He loved another woman. There was no reason why I shouldn't have a chance at happiness, too." Her daughter's back stiffens under her hand.

"What is your point, Mamma?" she demands and Mary all but flinches, for here is her younger self before her, hurt and heartbroken and lashing out.

"That I don't want you to make the same mistakes I did," she snaps, a little more sharply than she had intended. Her daughter is silent. "Your father went off to war, went missing, nearly died, and I still couldn't tell him that I loved him. And even though we got our happy ending - and not without a great deal of unnecessary pain and misery, I might add - I will regret that for the rest of my days."

Isabella mulls this over while her mother struggles for control. It doesn't matter how long it's been; the memories still cut mercilessly. It never fails to surprise her, how fearful she is of a fate long since avoided, of the precariousness of her past. She loves Matthew, he loves her; they have their family and Downton and the closest thing to a guarantee of happiness as anyone can get. Yet there will always be those nights when she wanders the halls, imagines the life she might have had , and has to check on her children, her husband, to make sure they are there.

"So, I should tell David how I feel," her daughter says quietly. It's a half-question. Mary smoothes a strand of Isabella's hair into place.

"My goal, as a mother," she replies lightly, "has always been to ensure that my children make a mess of their lives in an entirely different way than I did." Her daughter twists around, trying to gauge whether or not her mother is joking. Mary's lips twitch.

"Mamma," Isabella grumbles with all the weariness of an eighteen-year-old, and Mary cannot help but smile.

"I'm going to go tuck Edie in," she says, standing up. "I suggest you get a good night's rest and make a decision regarding David by tomorrow, as I can't make any promises that your father won't have him drawn and quartered by the end of the week." Her daughter nods, worn out. Mary is just over the threshold when a tiny voice speaks.

"Thank you," Isabella says. Mary's heart flops pathetically, but she gives her daughter another smile over her shoulder and closes the door behind her.

"Well done," comments Matthew in her ear. She starts, then swats at his arm.

"How long have you been eavesdropping?" she accuses him. Matthew looks at her rather balefully.

"I hardly think I can eavesdrop in my own house," he complains, but his arms as they draw her into his chest are gentle. She relaxes into him, letting him hold her. Only with Matthew does she feel true safety. "You needn't regret anything, you know," he says quietly. Her chest aches.

"I know," she replies, but they both recognize the futility of this old, old argument. She has let herself be happy, and that is the important thing; what price she pays for that happiness is another matter, less accessible and far more ambiguous.

"Mary," he murmurs. "Oh, Mary." He presses his forehead against hers, and she feels her frown slip away.

"Mamma!" an irritated voice pipes up from down the hall. Matthew grins. Mary groans.

"Nanny will have my head if I don't settle Edie in for the night," she mutters, giving her husband a familiarly careworn glance.

"Go, then, O Domestic Goddess," Matthew says fondly with a quick peck on the cheek. Mary rolls her eyes.

Later, when the house is still, she pads into her room after her rounds. She eases into bed, careful not to wake her husband, but an arm snakes around her waist to pull her close.

"I suppose I can't kill David, then." She can feel his chest vibrate with the sound of his voice. "If Isabella is so set on him."

"No, darling, you can't," Mary responds sleepily, curling into his heat. "They're much smarter than we were. They'll muddle through." Her eyes slip closed. "Give them time." Matthew chuckles, pressing a kiss to the crown of her head.

"My darling girl," he yawns. She smiles, and, comforted by the steady rhythm of his breathing, drifts asleep.

And there's no reason why I can't give the boy a good scare, Matthew thinks to himself, and, grinning, settles in for a well-deserved night's rest.