A Girl with Yaois

A teenage girl named Yuki, used to live alone. Her older brother was invited to a school far away and she didn't want to leave her friends. So she decided to stay in their crummy apartment, One day, she met 2 male teachers at a cafe. When they found out where she lived, they decided to take her in. She doesn't know they were hiding a dirty little secrets.

Yuki older brother, Mizuki, had to go to training camp because he for late for school everyday, and no one knows why. Before he moved and still with Yuki, she was worried, but he assured her. At the principal office, he met 2 seniors( both 3rd years) and they had to show him around the camp. I wonder, will they ever find out what cause him to be late everyday.