Sayaka and her son Kazuya live together in an old apartment. Although their life is not in affluence, they have lived peacefully without troubles. However, a tiny crack appears in their modest daily life as the uneventful circumstance surrounding Sayaka and her heart and mind show signs of change!! But one day... It was all of a sudden that Sayaka disappeared. Days after the disappearance of Sayaka, a DVD is sent to her son Kazuya... The DVD is labeled as "from Sayaka"...