Unhappy after his new baby sister displaces him, four-year-old Kun begins meeting people and pets from his family's history in their unique house in order to help him become the big brother he was meant to be.
上白石萌歌
as Kun (voice)
黒木華
as Mirai (voice)
星野源
as Father (voice)
麻生久美子
as Mother (voice)
吉原光夫
as Mysterious Man (voice)
宮崎美子
as Grandmother (voice)
役所広司
as Grandfather (voice)
福山雅治
as Young Man (voice)
本渡楓
as Baby Mirai (voice)
Jaden Waldman
as Kun (English version, voice)
