In a quiet corner of the city, four-year-old Kun Oota has lived a spoiled life as an only child with his parents and the family dog, Yukko. But when his new baby sister Mirai is brought home, his simple life is thrown upside-down; suddenly, it isn't all about him anymore. Despite his tantrums and nagging, Mirai is seemingly now the subject of all his parents' love.To help him adapt to this drastic change, Kun is take...