Tsuki wa Higashi ni Hi wa Nishi ni: Operation Sanctuary OVA

Synopsis

After losing his parents, Naoki Kazumi moves in with his cousin, Matsuri Shibugaki. Their lives take an unexpected turn when Mikoto Amagasaki, a girl from a century in the future, plummets from the sky onto the school rooftop. Mikoto has traveled back in time searching for her lost brother, but she mistakenly identifies Naoki as him upon their encounter.