Full House Kiss

Mugi Suzuhara was a normal teenager, until her beloved older sister disappeared. Shortly after, her parents died in a suspicious car accident after saying they had found her sister. Mugi tries to break into her sister's high school, Shoukei Academy, to find evidence, but is almost hurt by a guard dog when she's saved by Kazuya Midou, a rich and powerful student. He makes a deal with her that she can look around the school as a substitute teacher if she acts as a housekeeper for him and his three male boarders - who happen to also be very popular Shoukei students.