From Tasty Kiwi Scans:

HyoYi is a poor girl with a scholarship to one of the most exclusive private schools, attended only by kids from the richest families. Strong and resilient, HyoYi fights to protect her mentally handicapped brother whose disability makes him a target for bullies and beatings. Then she meets MinHa, who unexpectedly winds up making an agreement to protect the siblings. Bound together by their unusual arrangement, HyoYi and MinHa gradually learn what it means to love, one step at a time....