In a town blanketed by snow, a place from his distant childhood, Yuichi reconnects with his cousin Nayuki. As she gives him a tour of his new home, he struggles with memories long faded.

After his first day at school, Yuichi is able to stir the memories of Ayu, who happily recalls a promise he made to her years before. But the strange girl who later attacks Yuichi doesn’t seem happy at all.