Alice Rohrwacher’s Happy as Lazzaro sets out as a neorealist tale of exploited sharecroppers, but midway through the story it falls off a cliff (literally) and returns as magical realism, although we mustn’t hold that against it. Or should we? I was sad to see the first narrative go, frankly — come back! Come back! — and the second half rather lost me. This film is beguiling and intriguing and poetic (she says, defensively) but God knows why it couldn’t have carried on as it began, and God knows what it adds up to. I haven’t the faintest.

Written and directed by Rohrwacher (The Wonders, Corpo Celeste), the film won the prize for best screenplay at Cannes. It is set in a tiny hamlet in Italy that is also a tobacco plantation where the workers are so poor they sleep heaped on top of one another and share a single light bulb which they pass around. They earn no wages as the estate’s owner, the marvellously cruel Marchesa De Luna (Nicoletta Braschi), keeps them permanently in debt. However, this isn’t the 19th century, as there is the light bulb and glimpses of Walkmans and brick-like mobile phones, so it’s probably set at some point during the 1980s, when sharecropping was no longer legal but these workers don’t know that. (Apparently, this part is based on a true story.)

Our protagonist is Lazzaro (Adriano Tardiolo), a young man who has no immediate family and whom the community exploits in turn, albeit fondly. It’s ‘do this, Lazzaro’ and ‘do that, Lazzaro’ and ‘carry grandma inside, Lazzaro’. (Grandma is very, very old.) ‘I exploit them and they exploit him,’ notes the Marchesa. ‘It’s a chain reaction that can’t be stopped.’ Lazzaro certainly does nothing to stop it. Lazzaro is childlike and good and sweet and otherworldly. He will put you in mind of Forrest Gump or Peter Sellers’s Chance from Being There. And he always cheerfully obliges. He even cheerfully obliges the Marchesa’s spoilt, bitter son, Tancredi (Luca Chikovani), who comes up with a fake kidnap plot to extract money from his mother.

This is all beautifully told and beautifully filmed amid stunning scenery that is sometimes parched and raggedy and sometimes monumental (the mountains) and it is also beautifully involving. Lazzaro is so exquisitely innocent — Tardiolo may have the most exquisitely innocent face of all time — you desperately want it to work out OK for him. (Tell Tancredi ‘no’, Lazzaro. Just tell him ‘no’.) But then it (literally) falls off a cliff, which means that nothing is the same again. From here on in, it’s almost as if the film itself is suffering from some kind of hallucinatory concussion.

I don’t want to say too much, and give the game away, but the twist involves time spooling forward many years while the setting shifts from rural to urban poverty. Our characters are all here, and have aged, except that Lazzaro has not. There are other magical elements. Dream-like wolves prowl. Plants grow where they wouldn’t. I can do fantastical, but here it doesn’t mesh coherently with the neorealism that has gone before and it doesn’t create a consistent world like, say, Pan’s Labyrinth or similar.

Instead, it is confusing. What does Rohrwacher want to say? If this is allegorical, what’s the parallel? Is it the Christ story? Is it Lazarus rising from the dead? Or is it about capitalism and trampling all over goodness? This film is not a waste of your time, as it is also intriguing and beguiling and poetic (she says, still defensively). But the genre twist is far more audacious than successful. Alas.