Zhang Shutong once had two female classmates:One was the proud young lady of a rich family;One was the cool and distant young girl who was a temple keeper in the mountains.One of them was killed eight years ago, the other died eight years later.Zhang Shutong also has a secret that cannot be told:He can return to the past....But after going through all the trouble to save them, why are they fighting amongst themselves?...Deep mountains, a large lake, a shrine, shadows beneath the water, the serial murder case from eight years ago, and the young girl's gradually chilling body;This is a youthful story that takes place on a small island in winter, among a group of young boys and girls—a story that is somewhat heartwarming, somewhat thrilling, and somewhat romantic.