missing half-sakuatsu

1

it was Atsumu's second year of high school. it had seemed to be a day like any other, school was boring, Osamu, his twin, was too lovey-dovey with his boyfriend, and all he wanted was for practice to go smoothly and head home so he could finally wind down. 

practice went by quickly, with the usual drills and "punishment laps" he and Aran had to run because of some stupid jokes they couldn't keep to themselves. again, nothing out of the ordinary. 

"Tsumu, hurry up or you're walking home alone!" osamu yelled out to his twin, who was still busy getting changed and talking to Kita. 

"One second, I'll be right there Samu!" he yelled back, betting his farewells to all his teammates before hurrying to his brother 

their walk home was pleasantly uneventful. they walked together in a comfortable, even calming silence that didn't bother either of them. their silence was broken by Atsumu's phone, someone was calling him. 

"It's Mom" he quickly told Osamu, before answering and putting his phone on speaker. "hey Mom, you're on speaker. did anything happen? we're on our way home, we should be arriving soon"

"oh no, don't you worry about it, I was just calling to ask if you were staying out any longer tonight, I have something for you Tsumu, it's a surprise!"

that was..odd. surprises from their mom were not unusual for the twins, they were always receiving things at random from their mom, whether it was their favorite home-cooked meal, a new shirt, new games, and all that, but they never excluded Osamu. once their call ended, the two boys kept wondering what could Atsumu possibly get, and what was the surprise.

not long after arriving home, the twins were greeted by their mother with a hug and a dinner invitation. As they ate, the woman jumped up from her seat as if she had forgotten something.

"I nearly forgot! Tsumu, this came in the mail today, open it after you're done with dinner!" the twin's mom said excitedly, smiling from ear to ear with joy as she already knew what was in the envelope she just handed her son.

"I can't I'm too excited!" Atsumu then finished up eating and hurriedly opened the envelope which read "To Miya Atsumu, Inarizaki High". the envelope seemed very formal and was obviously important. he then began reading the letter inside.

"I was invited to a volleyball training camp! in... Tokyo.." Atsumu announced, seemingly worried.

"Isn't that great, Tsumu? you said you wanted to go pro after high school, this can be a great opportunity for you!" Osamu asked his brother, confused as to why he wasn't as excited anymore.

"Well, you didn't get one, which means I'll have to be alone in Tokyo for a week. we've never been apart for so long, ever"

"phones exist for a reason, idiot. you can always call me if you need anything, or if you miss me which of course you will" that last part Osamu said mockingly, even though it was partly true. he knew Atsumu was going to miss him because he was going to miss Atsumu as well.

a few hours later, Atsumu was in his room mindlessly scrolling on his phone, wondering what this camp could throw his way. although he was a very extroverted person, he had issues adapting to social situations without Osamu, which he wouldn't ever admit, but he still loved his twin and he knew camp was going to be weird without him there. 

Osamu knew that the blonde was very anxious, which worried him immensely, it made him think about how Atsumu would spiral and be all alone, without his support. Atsumu had had issues like this in the past, where he had trouble overthinking that people actually hated his guts, that he wasn't good enough to play, or that he could never compare to his teammates. this was going to be a challenge for Atsumu,  but Osamu thought it could be for the better, after all, you can never know what's about to happen.