A four-year-old's jealousy becomes the entire world, and the film never minimizes how real that feeling is to him. The garden opens not to grand spectacle but to quiet moments with versions of his family he's never met, each one teaching him something he didn't know he needed. Hosoda's direction transforms a house and its rooms into the kind of place where growing up and letting people in happen at the same speed, and the score settles into you like memory.
Four-year-old Kun's world shifts the moment his baby sister Mirai arrives home. Suddenly he's no longer the center of his parents' universe, and he resents her for it. Jealousy and confusion consume him until a peculiar garden behind his house becomes a portal to something impossible: encounters with his mother as a curious child and his great-grandfather in his youth, along with an unexpected visitor from tomorrow, his older sister Mirai. Each magical journey forces Kun to see the people around him differently. His mother wasn't always the reliable adult managing his tantrums. His great-grandfather was once young and uncertain. And the future Mirai shows him versions of himself he hasn't yet become. These strange adventures slowly reframe his understanding of family, time, and growing up. What emerges is a quiet meditation on childhood jealousy and sibling bonds, wrapped in whimsy and genuine warmth. This is a film about learning to share love rather than compete for it, told through the eyes of a small boy discovering that everyone around him has their own story worth understanding.