I don't own the Vorkosi-verse. All the lawyers out there satisfied? Good, 'cause I don't wanna get sued. Though if LMB wants to borrow from me, I'd be more than happy to acquiesce.

This one is dedicated to my sister and my very, very soon-to-be brother-in-law. Sis, I love you, and I wish I could tell you in words more eloquently than those I possess. Maybe Delia can speak for me, a bit. Bro, welcome to the family. Take care of her. Addition and Subtraction - family mathematics is a hard subject to understand, let alone master.

Winterfair.

Delia thought that Miles had certainly had the right of it, it was the perfect season for a wedding. With the snow and the ice making the world all crystal and perfect, it seemed only right to join hands with the winter spirits, donning white and becoming, for one glorious moment, a princess in your own right.

Or so it seemed to Delia, happily married already and looking forward to watching her younger sister Martya join the ranks of the blissfully wedded. She was the last of the Koudelka clan to do so, if one counted Kareen's rather odd arrangement with Mark as equivalent to marriage. Most people did, on Barryar, anyway. It was easier that way.

It had certainly taken Enrique long enough to pop the question, the eldest Koudelka mused. But, she supposed, in Borgos time he had been really quite speedy. Martya had once lectured all her sisters on the rather unique way the scientist approached the world, likening it to artists and composers who dropped out of the world for weeks at a time when the muse hit, only to emerge triumphant from the other side with a masterpiece in hand and a semi-wild gleam in their eyes. "He's a genius," she told them, haughtily. "And he's never ignored me when I need him, not even when he's nose-down in a test tube." Delia had chosen not to contemplate that image too long.

Now, here it was. Three weeks ago, Delia and Olivia were taking lunch together and wondering aloud when Enrique was going to stop stringing their sister along. Two and a half weeks ago, Martya had shocked them all when she'd come home from a walk in the park, sporting a large diamond on one hand, a huge grin on her face, and a blitzed-looking Escobaran in tow, and announced that they were getting married a week after Winterfair.

"Oh, good," Kou had said. "That'll give you a good year to prepare."

Drou, eyeing her second-eldest daughter warily, had laid her hand on her husband's arm. "Kou, I rather think she means this Winterfair."

Da had choked.

It had been a scramble ever since, trying to get everything ready for the spontaneous wedding. Martya and Enrique both insisted on small, and, Delia had to admit, the rather immediate timing of things was guaranteed to keep the gathering intimate: family, mostly, and a few select friends. Miles kept trying to appropriate the planning, but Ekaterin was able to keep him busy with the twins. The Vorkosigans had generously donated their home for the ceremony and reception and Ma Kosti was baking an enormous wedding cake guaranteed to lull the guests into somnolence and allow the bride and groom to escape early to their wedded bliss.

It was now a week to the wedding. Delia would have said that nerves were beginning to fray, but that would be untrue. The suddenness of it meant that most nerves had been flash-frozen. Da was operating on autopilot, and Delia was pretty certain her mother was nearly there herself. That had to be the explanation, as it hadn't been until that morning that Drou had yipped in sudden consternation, "Martya, you don't even have a dress!"

"I thought I would use yours, Mama," she'd said, simply, and Drou's eyes had filled with tears.

"Really? You want to wear my dress?" Delia could hear the catch in her mother's voice. Drou looked immeasurably touched, overtaken by emotion. Delia suddenly regretted her own blasé assurance to her mother that she would purchase her own gown new.

So here they were, that evening. Mama had pulled the vast white box out of the attic, and she, Delia, Olivia, and Martya were gathered around, waiting for the unveiling, the first time in three decades that the dress had seen the light of day.

Mama carefully sliced through the airtight seal on three sides, and nearly reverently peeled back the top layer of plastic. All four women caught their breaths as the beautiful white silk came into view. They'd seen pictures, naturally, but it was one thing to view it in a tinny holo, worn by a younger version of the woman they had only ever known as much older, and quite another to be looking between it and Martya and wondering how it would look on her. Quite elegant, Delia was sure. Well, Martya was a Koudelka; all trim, leggy blonde irregardless of the fact that she didn't care much about her appearance.

Mama's hands caressed the silk, eyes staring into the distance, lost in memory. Olivia helped her lift it out, marveling at the long falls of shimmering material. Delia's eyes caressed the lines, the intricate stitching, the tiny seed pearls scattered over the bodice.

Martya's eyes glistened as she looked at it, and Mama shooed her other two daughters out of the room to give them some privacy. Olivia and Delia spoke quietly, though Delia wasn't quite sure what about. Her gaze kept drifting to the bedroom door, and she noticed Olivia's doing the same. Finally Mama opened the door and beckoned them inside.

"Oh..." Delia's breath puffed out as she stared at her little sister. She looked like a bride. There was no other word for it. She was absolutely radiant, and Delia realized for what felt like the first time that her baby sister was a woman.

And that she would be losing her.

Not really, no. Martya would always be her sister, would always be one of the Koudelka clan. But in one short week, she would be a Borgos. Something Tante Cordelia once said echoed in her mind. 'The two will be united and become as one flesh.' It had the ring of Tante Cordelia's religion to it. Delia had never much paid attention to religion, but right now, she thought she understood. Martya was about to change.

Swallowing hard and blinking back tears, Delia hugged her sister. "You look beautiful," she whispered in her ear. "Enrique is a lucky man."

Martya hugged her back. "I love you, Dee," she murmured.

"I love you, too, Mar."

The sisters parted, and after a bit more ooing and ahing, the dress was hung up, the veil pinned back to its card, and the wrinkles smoothed out.

Delia hugged her mother extra hard that evening before she went home to Duv. They didn't exchange any words, but Delia imagined she knew what her mother was feeling. Their family was both growing and shrinking at the same time.

It was a curious sort of arithmetic, all things told.

That night, Delia held Duv tight, her own personal addition and subtraction, and thought that she was very lucky and very grateful that she'd have him by her side for the rest of her life. And, more immediately critical, for the rest of the week. He laughed and made a joke about weddings being catching, and she laughed along with him, and then they made sure to forget about everything else in the world for the short time until dawn.