Yuichi Aizawa returns to a city he visited once, seven years ago, when he was young. He remembers almost nothing of what happened there. On January 6, 1999, he arrives to stay with his first cousin Nayuki Minase and her mother Akiko, detached from his surroundings and uncertain of anything he might have left behind. Nayuki tries persistently to help him remember, without success. As Yuichi begins to understand the city's quiet supernatural undercurrents, fragments of those lost seven years start to surface.