Mirai

Kun, a lively 4-year-old, enjoys a joyful life with his architect father and executive mother in a uniquely designed stepped house. He spends his days playing with his pet dog Yukko and engaging in imaginative adventures with his toy train sets.

The peaceful dynamic of Kun's life changes with the arrival of his baby sister, Mirai. Initially excited, Kun soon feels neglected as parental attention shifts to the newborn, leading to feelings of jealousy.

After a particularly frustrating day, Kun has an outburst and retreats to the garden for some solitude. There, he meets a mysterious man who claims to be the ‘prince’ of the house, soon revealing himself to be Yukko transformed into a human.

Intrigued by the 'prince', Kun playfully puts on a tail resembling Yukko's, triggering a magical transformation that turns him into a dog. This whimsical change sparks a series of imaginative adventures in Kun's mind.

The family celebrates Hinamatsuri, a special day where they display traditional dolls to wish for Mirai's happiness. However, as days pass, Kun feels frustrated that the dolls have not been put away, resulting in another outburst that sends him back to the garden.

In a surprising turn, Kun meets a teenage girl who identifies herself as Mirai from the future. She explains the urgency of returning the dolls to avoid delaying her wedding, and the two work together, alongside Yukko, to resolve the situation.

Kun ventures into the garden once again, enabling him to journey back in time. He encounters a younger version of his mother, allowing him to witness her childhood struggles and to connect more deeply with her experiences.

Kun receives a bicycle with training wheels after leaving a heartfelt note. Eager to ride like the older kids, his determination leads him back to the magical garden, where he meets his great-grandfather and learns valuable lessons.

During a family outing, Kun's frustration about his clothing leads him to explore the garden once more. He discovers a train station and, despite a warning from an older young man, he boards a train and finds himself lost at Tokyo Station.

While at the train station, Kun struggles to remember his parents' names but realizes he must rescue baby Mirai when she is about to board a train to 'Lonely Land'. This incident marks a pivotal moment in Kun’s acceptance of his responsibility as an older brother.

Kun is greeted by Future Mirai, who returns him home in a spectacular fashion, soaring through the air to land safely in their family tree. This experience provides Kun with a broader perspective on family and the connections they share.

In the family tree, Kun witnesses pivotal moments from his family's past, including his father's challenges, Yukko's choice to become a pet, and the historical impact on his great-grandfather. He also catches a glimpse of his future self.

After his journey through time, Kun emerges with profound insights and understanding of his family’s dynamics. He recognizes the importance of empathy and connections, feeling more ready than ever to embrace his family.

Equipped with newfound wisdom, Kun rejoins his family for an adventure, now fully accepting his role as an older brother. This marks a meaningful change in his attitude, reflecting a deepening of familial bonds.