Taika Waititi detonates an explosion of postmodern quirkiness and ironic dorkiness in this unbearably mannered, unspeakably acted film. It’s a slice of sentimental whimsy-futurism and non-satire, adapted by Waititi from the Kazuo Ishiguro novel, which winds up saying nothing substantial or meaningful (or funny) about artificial intelligence, love or grief. Klara and the Sun is soft-centred sci-fi-lite, simultaneously demanding we laugh at its (unfunny) humour and wipe away a tear at its pass-agg poignancy. With earlier films like Hunt for the Wilderpeople and Thor: Ragnarok, Waititi showed he can do comedy. But this, sadly, is closer to his notorious fey-Hitler fantasy – misjudged and self-admiring.

In the world to come in an uncanny valley of the almost-real, families can buy “artificial friend” or AF robots for their kids. In terms of tech plausibility overall, incidentally, their status isn’t entirely clear: AF salesperson (Natasha Lyonne) says that the recent third world war has wiped out the internet. (This post-WW3 world looks in pretty good shape apart from that.) And these AF humanoids incidentally have a kind of purple blood called PEC-9 running through them which one character incidentally tells us is “highly flammable”. (Uh-oh. Quite the design fault.)

One such AF is teen girl Klara, played by Jenna Ortega as a ditsy, cutesy, supremely lovable innocent: a manic pixie dream robot – only nice – who is solar-powered and who therefore, in her adorable childlike robot way, worships the sun as a god. But Klara is an earlier, more rudimentary AF model, less sophisticated and robust apparently than the newer upgrades which run on Bluetooth as opposed to solar. (Is that really better?)

At all events, her flaws are presented as analogous to the vulnerabilities of the human teen who wants Klara; this is Josie (Mia Tharia), a 14-year-old genius-prodigy due to be expensively “lifted” into a super-IQ class via a new surgical procedure, but who is also very lonely and suffering from an unspecified illness. Her uptight mom is played by Amy Adams and the grumpy housekeeper Melania – whose appearance is the nearest the film comes to comedy – is played by Rachel House. Klara goes to live with her new family in their distant home in a weirdly dreamlike Midwest farming landscape from which the city can only be glimpsed distantly, like Oz. Klara becomes certain that the sun lives in the nearby barn above, from which she can see it rising every morning; what a sweetly naive belief. And so it goes on, to a twist ending that is as unsatisfying and contrived as everything that has gone before.

The thought of robots or replicant youngsters having real intelligence or real feelings is a difficult subject; Hirokazu Kore-eda came unstuck with the idea of robot child replacements in his recent film Sheep in the Box. Kogonada’s parable After Yang, about AI child robots, was a more interesting and persuasive movie. But this is a sentimental and laborious mess.