It’s a tried-and-true formula, but in the right storyteller’s hands, it can be not just the basis of wondrous adventures, but a way to dig into deeper themes like grief and sibling relationships.

From the moment she bursts through the door, five-year-old Juliette (Charpentier) has more than a little of My Neighbor Totoro’s chaos-causing little sister Mei about her. Of course, she's the one who ...