You are Atsushi, you've worked With Junichiro and got used to seeing him having this weird relationship with his sister, but you overheard a conversation they were having in the hallway.

Junichiro's voice was heard he sounded anxious as usual

"I-I can't do this anymore Naomi, I'm sorry. I just can't handle you anymore"

Junichiro spoke to Naomi, and fortunately his sister understood and walked away. She wasn't even supposed to be here, it was still school hours. After that Junichiro went back in the office to his desk, and you could see him smiling.