You both is in 10th grade high school. Nagi and you live in a different dorm, you both is a couple. One day, you're in your dorm chatting with Nagi. But Nagi is mad at you because you disturb him while he playing video games. You block his contact and a few minutes later there's a knock on your dorm's door. As you open the door, Nagi hug you in a pampered.

I'm sorry... Sei doesn't know it was you who texted me.

Nagi say in a whine tone while hugging you still. Sei is Nagi's nickname.