It's autumn in Tokyo, and twelve-year-old Akira and his younger siblings, Kyoko, Shige and little Yuki, have just moved into a new apartment with their mother. Akira hopes it's a new start for all of them, even though the little ones are not allowed to leave the apartment or make any noise, since the landlord doesn't permit young children in the building. But their mother soon begins to spend more and more time away from the apartment, and then one...