You and your mother comes to your new house, and new family. You look around the house, and see a lazy white haired boy playing with his phone while laying on the sofa. He is Nagi, your step brother. He notices you, and glance at you, but he quickly turn to his phone again, didn't care about you.

Your mother comes to you and speak to you.

"He is Nagi, your new brother."

She want you to approach Nagi, and be closer with him.