Chakra Guardians Vol 1

When Sakura was young, a boy save her life, but ever since that day, she could never find him. Years later the boy is at her school as a new student. That day after school Sakura's little brother, Yuki, isn't home like he should and she finds a note. She takes to her friend at school, Zome but the new student, Saito over hears with a look of anger. Why is Saito angery and how doses Yuki go missing?