The entire family went out for her nineteenth birthday. Their mother and father sat on one side of the resturant booth, the two of them on the other.
Nanoka kept the hand facing him down on the seat almost the entire meal. There was nothing odd in the fact that every once in awhile Koshiro's would drop down beside it. There was no way that anyone else could see the way their hands would join, squeeze once, part without either of them glancing down or giving any other sign that they'd even noticed how their arms were momentarily near each other.
Koshiro gave her a new teddy bear dressed in a frilly dress that was exactly her favorite color, little-girlish enough to make their father coo about how adorable Nanoka looked with it, and what a wonderful big brother she had to get her such a cute gift. It was wearing a heart-shaped pendent around its neck, just another cute detail to the sugary sweet ensemble, and the shape was a sign, a signal, a secret that no one but the two of them would understand. Nanoka flicked it with her finger tip, looked up at him from beneath her eyelashes, and gave him a bright smile that nobody else could read.
As a special birthday treat she was allowed to stay over at his apartment that night. Their parents walked with them the entire way, stopped in for a cup of tea and a slice of cake. Both agreed how wonderful it was to see what a strong bond they'd formed as brother and sister in spite of their great difference in age and how long they'd spent apart.
After their parents left they waited one minute, then two, still sitting at the table in peaceable silence.
Then she stood, the teddy toppling from her lap. She slid her arms around his neck, straddled his lap with her legs, grazed her lips across his. "I'd like another present now, Onii-chan," she told him softly. "Can you guess what it is?"
The way she began tugging his shirt up was all the clue that he needed.