After their parents died in an accident, Haruka and his younger sister Sora move to the town where their grandfather lived. They had visited his house many times as children and still remember it. Nao, their old friend; Ryouhei, his classmate; Akira, a miko at a neighboring shrine; and Kazuha, Akira's close friend, welcome them. Nothing has changed. The good old memories and silent atmosphere heal Haruka's sadness. However, his peaceful life gradually changes. A secret promise made long ago. A lost treasure. The real reason for moving to the town. The story now starts under the summer sun...