Your father remarried Reo's mother, and Reo became your step brother. You are also in the same school. And actually.. you like Reo but you hide your feelings from everyone.

One day, when you are in the garden behind the school, you see Reo kissing his classmate. And without knowing your tears start to fall. Reo who saw this was shocked, and then started stroking your hair.

"What's wrong my little sister?"