AN: I've wanted to write this one for a while, considering that Isobel is her mother - in - law, Mary and Isobel don't share enough scenes.

This particular conversation was inspired by a deleted line from the wedding, in which Isobel is asked by a guest if Mary is 'nice'. Isobel doesn't concede 'nice' (quite correctly) but does say that she thinks Mary is right for Matthew.

They don't share many conversations so I guessed at their dynamic a little, but I hope you enjoy!

As Mary walks purposefully down the path leading to Crawley House, she finds herself feeling rather more nervous than she'd expected. She's surprised since these days not much seems to phase her, and this is just Cousin Isobel. Just...Matthew's mother. The woman who raised him, who he looks up to more than any other. A woman Mary is aware has not always been her biggest fan, who may have pictured Matthew with someone rather different, someone milder and kinder. Perhaps even someone more like Lavinia.

When she'd refused Matthew before, driven him away with her indecision and inability to commit herself to him, let alone tell him about Pamuk, Isobel had remained. They'd spoken only rarely, and about nothing of consequence, across the table at dinner or over a bed in a ward. However, she'd often found the older woman's eyes on her when she thought she wasn't looking, eyes that held a hint of sadness, and occasionally anger.

Now that she and Matthew have finally made it right, finally committed themselves to each other unreservedly, Mary feels the need to make amends with Isobel. She knows that nothing will change Mathew's mind about her at this point, not after hearing her darkest secret and loving her anyway, but she wants to feel sure that the elder woman understands how she feels about him, that she knows this isn't simply her staking her claim on the heir. She wants her to know that she truly loves her son.

Reaching the door to the house, she knocks, steeling herself for the conversation ahead. She and Matthew plan to tell them all at dinner, but she feels she must talk to Isobel first. She knows he won't exactly be pleased that she's told her, but she thinks he'd understand if he found out.

The door swings open, and she finds herself face to face not with Molsley as she'd expected, but with Isobel herself.

The other woman looks momentarily surprised to see her but quickly puts on a smile.

"Mary! Come in! If you're looking for Matthew, I'm afraid he's gone out."

This, Mary knows. She'd chosen a moment where she knew Matthew would be absent, attending to some estate business with her Father.

"It's you I came to see, Matthew doesn't know I'm here."

"I see," says Isobel "I'll ring for tea."

She does so, and Mary finds herself ushered into the sitting room and shortly settled down with a cup of tea that she's glad to have if only to keep her hands steady.

Before she can launch into her reason for being there, Isobel surprises her by speaking.

"Before you say anything, I feel I should tell you that Matthew told me he proposed and that you agreed" here she pauses "and Mary, I'm so very glad, you both deserve to be happy."

"He told you?" Mary says, aware that she cannot be too cross, for she'd been about to do the same thing.

"Yes, and you mustn't be angry. He was so happy when he came home last night that I guessed, I'd been rather hoping for it you see. I saw how unhappy you both were the other day, and I saw that you still loved him, told him as much."

Mary smiles "I'm not cross, in fact it makes what I've come here to say much easier."

Here, she pauses, and sees Isobel tilt her head ever so slightly, waiting unusually patiently for her to continue.

I.. I know you haven't always approved of me, that you felt I treated Matthew rather badly before the war."

Isobel sighs, but regards Mary with eyes that hold such kindness that they give her a little hope.

"I must admit to being rather disappointed in you back then. I saw how much he cared for you and it seemed at the time like you were just stringing him along, listening to all the wrong people and making such a mistake. That was hard to watch. Of course, I blamed Cousin Violet and not you entirely, but still. "

Mary smiles slightly at this last comment, but looks down at her hands, this is what she'd feared. However, she wants her soon to be mother in law to understand, so she continues

"It was hard for me back then, I never expected to marry for love. Patrick and I..."

Here, she pauses, thinking of that long-ago day when Papa had sat her thirteen-year-old self down in the library. He'd explained that the doctor said Mama could have no more children, that Patrick's father would now be recognised as the heir, and if she wanted to make sure she could stay at Downton, give Edith and Sybil security, she'd one day have to marry him.

She'd been thrilled to think of herself as a Countess back then, proud that Papa was trusting her with something so important. She'd not known then the toll it would come to take on her, the way it would change the way she saw the world and herself.

Seeing Isobel's quizzical expression, she pulls herself out of her reverie and continues "We'd been expected to marry since we were children, everyone wanted it, thought it best."

She sees understanding dawn on Isobel's face. "Because he was the heir? Even though you didn't love him?"

Mary nods her head "Yes. I liked him of course, and we were friends, but I didn't love him. I'm not trying to pull rank, but for people like us, it's not expected, not seen as important. Of course, if it comes later then that's a bonus, but… it's rare."

"It came for your parents."

This is true. "It did. But even as a child I knew they were unusual, lucky to be so well suited. I didn't expect it would ever happen to me. I was taught to be pragmatic, to consider position more important than love"

"I see."

Mary begins to think that she does "So, when Matthew proposed, and then Mama became pregnant, I didn't know what to do. "

"Because at the time, you weren't sure you were in love with him, and it seemed as if he'd have no position? You thought you may end up with neither?"

Suddenly, although she knows that the majority of her family believes this to be true, thinks that she'd only grown to love him afterward, during the war, she realises she cannot allow Isobel to think this.

"Oh Isobel, I think I've been in love with him almost since we first met."

Here, she expects Isobel to be shocked, express disbelief. She's not prepared for what she actually says.

"I suspected as much. Oh no, I didn't think it'd been quite that long, and I didn't know that you'd realised it yourself, but I talked to Violet at that garden party, and then later saw how you looked at him when you first saw him with Lavinia, and I wondered what you might have felt."

Mary looks down at her hands, recalling how painful watching them together had been. "It was hard to see them together. Even more so because I liked her"

Isobel smiles "She was a dear sweet girl."

She presses on "So when you turned him down before, let him think you were considering him only because he was the heir, you were in love with him?"

"I was, or at least I was fairly sure I was"

"Then why refuse him?"

This, Mary knows to be a fair question, if not one with a clear answer. She's not quite ready to tell Isobel the story of Mr Pamuk.

"There were so many voices on either side, my own telling me I loved him, all the people who had urged us together before, Granny, Mama, Aunt Rosamund, now urging restraint, that I wait and see what his position would be if he'd inherit. None of them knew or thought that I loved him, not really."

She sees understanding appear on Isobel's face.

"And despite your feelings, you listened?"

"I listened, I let them amplify my own doubts and mask the love I felt, I ruined everything and drove him away."

"How very sad. I must say it makes me rather angry."

Mary feels her face become stricken, and it is immediately clear that Isobel sees it, as she quickly moves to clarify

"Oh no, not with you, just with a system that forces young women to push aside what really matters, push aside their own happiness."

This is an anger Mary has more than shared in the past, and while she won't share as much with Isobel, she finds that on this subject they are quite in agreement.

Then suddenly, she sees a smile grow across Isobel's face.

"But having heard this, I'm so very happy for you both. Truly Mary, telling me this took real courage and I can see how much you love him. Maybe as much as he loves you. I understand now that you never meant to hurt him/"

"Thank you, Isobel, that means more than I can say," Mary says, aware that the relief she feels colours her tone.

"I'm glad. But I must ask, have you told him?"

"That I truly loved him even then? No. I don't want him to regret anything he had with Lavinia, and I think it would make him sad even now."

She watches Isobel consider this.

"That's admirable. But I think he would want to know. He loved Lavinia, I know he did, but I also know he has always loved you. I think he'd want to know that it was reciprocated."

Mary sighs "perhaps, but how to tell him?"

Just then, a new and very familiar voice joins the conversation "how to tell him what?" Matthew says, entering the room, surprise showing on his face at who he finds there.

"Mary! What are you doing here?"

Isobel replies before Mary can gather her wits "she came to see me" and then wickedly adds "she has something to tell you" before leaving the room and closing the door behind her.

Matthew watches her leave, and she can see twin expressions of annoyance and amusement appear on his face. He then turns to face her "I'm assuming you know I told her, I'm sorry darling, I know we were going to tell them all tonight, but she guessed something had happened."

Mary smiles at him, quick to put him at ease "She told me she guessed, it appears we were less subtle than we thought."

He sighs with what is clearly relief before moving to sit down next to her. "Thank god, I didn't want to start off tonight with you cross at me".

Then, just when she thinks he'd forgotten his mother's earlier words, he asks 'then what is it you wanted to tell me?"

"Something I told Isobel, that she thought you'd want to hear."

"Oh?"

She pauses for a minute, thinking about how to approach this. "She asked me when it was that I first knew I loved you, and she thought you'd want to know the answer."

"So I would". Then, he takes on a playful tone "let me see if I can guess. Was it… when I punched Sir Richard for insulting you and Lavinia"

"No" she says, recognising that he's teasing, and deciding to play along.

"Hmmm, then when we danced that night, in the hall."

She smiles, remembering. "No, not then either."

He quirks an eyebrow at her "Even earlier? My. How about… when you saw me again during the concert?"

She rolls her eyes at him "Wrong again I'm afraid.", she says, aware now that he's working up to name the time he actually believes it was and wondering if he'll be right.

'Oh, I know when it was, how silly of me." Here he pauses, she thinks for dramatic effect, and says what she knows he believes is the truth "when I first proposed, after rescuing Sybil

This is what she'd suspected he'd say. "Not then either, though that's certainly the night I allowed myself to admit it properly to myself."

He sighs, and says in a tone that carries a hint of regret "I wish you'd been able to tell me this then, though I understand why you couldn't."

She knows he truly does, knows now that it was the shadow of Mr Pamuk and the meddling of her family that had prevented her accepting him the first time, not her lack of feeling.

"Darling, if not then, when was it?"

Ready now to tell him the truth, and sure he can take it, Mary does.

"The first time we met, in this room, with you proclaiming that you wouldn't let Mama and Papa push one of us at you."

His mouth drops open, and he takes her hand in his.

"Truly Mary? All this time?"

She nods, and sees how deeply touched he is by her proclamation. She's expecting his reply when it comes, but it still fills her with love, albeit tinged with regret at what might have been.

"Me too darling, me too."

Outside the drawing-room, Isobel finds herself overcome with emotion as she overhears the end of their conversation. The journey the two of them have taken to get here may have been longer than necessary, and longer than any of them would have liked, but they've finally made it.

She's very sure that the two of them will continue to fight, they're both far too strong not to, but she also finds herself thinking how very certain she is that in the end they'll be happy. And, she thinks, Mary might not be the 'nice' girl she'd sometimes envisioned, but she clearly adores Matthew and is right for him. What more could a mother want for her son?