After his mother remarries, Junya finds himself with a younger stepbrother in high school. While his parents are on their honeymoon, his new younger brother Kyouichi comes to live with him in the same house. Kyouichi was nice to Junya when he had his heart broken. He's a good, straight-laced student, and Junya wishes Kyouichi would depend on him more, while his feelings for Kyouichi also grow. Then, one day, Kyouichi suddenly kisses Junya!