Kinkyori Renai: Season Zero

Haruka, Mirei and Kanata are high school students, and they are good friends. Suddenly, Haruka’s older sister Ririko returns to Japan. Haruka and Ririko are not blood-related. Ririko hasn't been to Japan for years, and she now looks beautiful. She is so beautiful that people call her "goddess." Ririko approaches her younger brother, who is reluctant to associate with other people.
One night, Ririko cries into her younger brother's chest. Haruka is embarrassed Ririko approaches him, Mirei has feelings for Haruka, and Kanata realizes this.