Tetsuko “Alice” Arisugawa (Yu Aoi) is a writer’s daughter, cursed with an over-active imagination. Shunted into a new school by her parents’ divorce, she finds the perfect foil in local truant Hana Arai (Anne Suzuki), a pathological liar who eggs her on into wild conspiracy theories, breathless scandal-mongering and a series of misadventures that grow hilariously out of hand.

A decade after his early success with Hana & Alice, a live-action comedy about two hyper-active schoolgirls who dupe a boy with amnesia, director Shunji Iwai decided to revisit his characters with a prequel about a fateful day that saw them stranded in Tokyo and inadvertently starting a missing-persons hunt. The film’s title, The Case of Hana & Alice, makes it sound like some bloodthirsty murder investigation, a fitting evocation of the leads’ compulsion to read melodrama into everyday situations.

“The thing is,” Iwai laughs, “you can get away with a lot more when you’re a girl. Look at Hana and Alice and the way they behave. In the first movie, they were basically stalkers, telling that poor boy that they had a past together. In this prequel, they are causing all this trouble around the city. They’re kind of… how can I put this? They’re perverts. If I made that story about a man, if I made it about you, for instance, then you’d be locked up.”

It would also have been impossibly expensive as live-action. It wasn’t just a case of redressing Tokyo to look like it was 2004 – the film’s plot demands an absence of social media, as many of its escalating misunderstandings could be halted today by 20 seconds’ Googling. But the original film made stars of its leading ladies, who were not only now out of Iwai’s price range, but pushing 30 and unconvincing as middle-schoolers. Iwai hit on a solution inspired by the films of Ralph Bakshi. He shot the entire film on the run in 30 days, using teenage stand-ins for the stars, and then painting over every frame to make it look like an animated film.

After the guerrilla film-making was done, the touch-up was outsourced to 150 freelancers all around Japan. Iwai denies that he ran the whole post-production process without having to get out of bed, but one can easily imagine him pottering around his living room in a dressing gown, watching as digitised packets flow in and out of his server. The expensive leads were lured back for a single day to record just the voices; their younger onscreen selves moved and emoted like the teens they really were, and digital effects fixed the lighting and scrubbed out buildings and technology that did not exist a decade ago. The result might look on the surface like an animated film, but the use of live actors delivers huge amounts of nuanced data – flinches, tics and micro-expressions that would simply never happen in a cartoon.

The real charm of The Case of Hana & Alice is the compassion that suffuses the film. Two clueless kids, poised on the cusp of adulthood, go AWOL overnight in a big city, but are kept safe by the good deeds of the people they meet, from the taxi driver who waives an unaffordable fare, to the indulgent strangers who put up with their histrionics. There’s not a dark moment in a film that is as confident about its leads’ right to be silly as it is about the surety that all will be well in the end. The Japanese, unsurprisingly, have a word for it: omotenashi, or kindness for the sake of kindness.

The Case of Hana & Alice is also a winning portrayal of the slippery relationship that teens have with the truth, although Iwai himself says the original inspiration came from somewhere much closer to home. “When I started working in the film industry, I was astonished at how many of the people there were bare-faced liars. There are an awful lot of them, like half! It’s very surreal, and that provided a lot of material for Hana.”

Jonathan Clements is the author of Anime: A History. This article first appeared in Geeky Monkey #16, 2016.