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Invited by Teratani to a study camp by the sea, Kazuki meets Izumi Isozaki, a girl standing alone on a rocky beach!　He is shocked and depressed by her disdainful gaze. Izumi tells him about a 51-stone spell that protects their love, and he decides to pile up the stones on behalf of Izumi's ex-boyfriend. And the last white stone he piles up is...