Sibling envy is at the heart of this intimate yet kaleidoscopic anime, the first of its genre to premiere at Cannes, in which four-year-old Kun (Moka Kamishiraishi) must come to terms with the arrival of his baby sister, Mirai. His tantrums send him spinning off into fantasy rendezvouses with relatives whose loftier perspective enables the youngster to get a handle on the cute calamity cramping his style: among them, teenage Mirai; his mother as a girl, whose unruliness is strangely familiar; and his Brando-esque great-grandfather, wounded in the war.

A virtuoso tracking shot up and down the five tiers of the crisis family’s house swiftly confirms that Mamoru Hosoda, founder in 2011 of Studio Chizu, is an anime adept. The film, continuing the emotionally astute work on show in Wolf Children (2012), shuttles just as fluently between the various generations.

The fantasy sequences – whether they’re Kun’s imagination or something more magical isn’t clear – are lavish; gothic ruins and fish-filled waterspouts exploding out of Kun’s garden refuge convey his inner upheaval. Just as in a four-year-old’s mind, the trivial and the epic are synonymous. Helping future Mirai retrieve a ceremonial baton stuck to his dad’s trousers becomes a cliffhanger action sequence. The sequence in which, inspired by his great-grandfather, Kun rides a bike without stabilisers for the first time plays as a Rocky-like triumph.

Mirai definitely puts Hosoda in the Japanese industry’s top league, showing a similar spirit of high-blown romanticism as Your Name (2016), anime’s high-water mark in recent years. It doesn’t, though, quite have the same degree of narrative mastery: a few flat transitions back to reality and weakness for drenching Kun’s reconciliations in cutesy overkill dull its finish. But Hosoda’s delicate, painterly style is perfect for capturing Kun’s evanescent imaginary haven – and conveying the message about the moral courage needed to leave it.