My Blood & Bones in a Flowing Galaxy

Hamada Kiyosumi is a 3rd grader in high school. He possesses a strong sense of justice. One day, he sees first-grade student Kuramoto Hari being bullied. He helps her. Since that time, Kiyosumi has tried to save Hari from bullies. While doing that, they grow closer.
(Source: AsianWiki)
~~ Adapted from the novel by Takemiya Yuyuko.