Hoshi no Harmony 

This manga includes two different stories. 1) Hoshi no Harmony (2 chapters) : The first one is about a girl, Yukiko, who is always doing what others tell her to do and a boy, Wada, who can't stand how his classmates always taking advantage of her naïveté and kindness and tries to knock some sense into her. 2) (4 chapters) Mayuko and Sugikake's story : Mayuko had an unrequited love with her cousin and promised herself to not fall in love again but everything changes when Sugikake, her sempai in the volley club, starts picking on her.