Mirai

Four year-old Kun is disappointed when the new baby in his family promptly replaces him as the center of attention; he refuses to accept his little sister, Mirai. When a magical and mysterious gateway opens in the garden, Kun has the chance to encounter his family members when they were young themselves. He is also visited by an older girl with the same name as his sister, leading to a series of surprising adventures, which change how he sees the world.—Anonymous