Yuichi Aizawa returns to a city he hasn't visited since childhood, moving in with his cousin Nayuki Minase and her mother Akiko. Seven years of absence have blurred nearly every memory of what happened here, and Nayuki's attempts to jog his recall keep hitting the same wall. As winter deepens and strange things begin to surface in the city, Yuichi's forgotten past slowly comes back—and with it the supernatural threads that were always woven through his time here.