Kun enjoys a happy childhood until the arrival of his baby sister, Mirai. As the new baby becomes the centre of his parents’ attention, he becomes increasingly jealous. Little by little, he withdraws into himself. In the backyard where he likes to take refuge, grows a magical family tree. Kun finds himself suddenly catapulted into a fantastic world where the past and the present mingle. One after another, he meets his relatives at different ages. Through these adventures, Kun is able to discover his own story.
As a four-year-old boy has a rather limited perception of his environment, Mamoru Hosada decided, what better to illustrate this idea than the house and the garden? They should play an important part in the story because to children, they are like an entire universe. Therefore, the design of the house was enlisted to an architect who worked on the project as though he were planning an actual house, carefully studying the space, the light, and the materials. This resulted in a house that is neither typically Japanese nor western, one more akin to a theatre stage with its succession of landings and absence of partitions.
"Through a house, a garden, and an ordinary family, I wanted to evoke the great cycle of existence and this circle of life that we all weave, individually. I like using the small events in our lives as a basis to tackle its most important themes. Using entertainment as a medium, I wanted to explore a new means of expression that would be in sync with the concept of family in its newest forms. And although it may not be sensational in appearance, this film carries my deep personal ambition."
- Mamoru Hosoda