Darkness of the Sea, Shadow of the Moon

Umi no Yami, Tsuki no Kage

Lumi and Luka Kobayakawa are identical twins who both are members of the track team and have a crush on a handsome upperclassman Katsuyuki Tohma, but he chooses the latter. While Luka doesn't want to hurt Lumi's feelings, Lumi feels betrayed by her own sister. On their way to the party celebrating the graduation of eldest members of the team, they take shelter in a cave, which ...