It's a gorgeously animated Madhouse anime movie. It's charming, funny and entertaining. What's more, though, that charm's nature is why I can't remember seeing a better dramatisation of computer hacking.

There are two worlds in this film: the real one and the virtual one. The latter is called Oz and it looks stunning, with inhabitants who resemble cartoon characters. Imagine it as Facebook, Google or Twitter, but with an even better business model. Oz virtual identities are so convenient and universally accepted that people use them all over the place as all-purpose electronic passports. This sounds like a great idea and makes life easier for everyone until something called Love Machine starts stealing those virtual identities and making trouble.

Despite the name and eye candy, though, the film has a clear-headed view of Oz. It's not a magical land of fantasy. Dorothy doesn't get sucked there from Kansas. It's just part of the internet. Everything there has a real-world cause and effect. Furthermore, it's realistic. Everything it depicts is easy to imagine, to an extent that's almost prophetic. Two years before the Fukushima Daiichi nuclear disaster, this film's finale threatens an accident with a Japanese nuclear reactor.

Then there's the real world. Kenji is a high school student who agrees to accompany a fellow student (Natsuki) to her grandmother's 90th birthday celebration. They go off into the countryside and find that Natsuki's grandmother is on first-name terms with half of the government, lives in a castle-like estate and has about eighty raucous relatives. Those relatives are what makes this film's animation so stunning, by the way, not Oz. They've all come to pay homage to granny and there's liable to be ten times as much happening on-screen as you'd get in another animated film (anime or otherwise). It's like watching Ghibli. Anyway, life's never quiet when the horde is around, which is all the time. Pretty much any kind of relative you could imagine is present. They're intrusive, pushy and lots of fun.

Anyway, Natsuki's family is the lens through which we see the unfolding virtual events... or is that the other way around? The film never falls into the trap of making Oz important in itself, but instead keeps thinking about what its events would do in the real world. This is all-important. Real-world problems aren't a bunch of statistics, but granny, the unsociable schoolboy and the birthday food. This is charming and ensures that you care about what happens. On the downside, lining everything up for the plot to work does create a significant coincidence factor, even if the script mostly manages to sell this. (I thought it did. Tomoko thought it didn't.) More specifically, Kenji is some kind of semi-autistic number-crunching genius, although that I don't mind since it's practically the first thing the film tells us. Natsuki's relatives can make almost anything happen, but that's not so surprising given: (a) how many of them there are, and (b) granny. Wabisuke is... okay, there I think we've just got to swallow the improbability.

The main characters aren't as colourful as they might have been, but that's because the most vivid characterisation here is the family as an outrageous whole. Kenji and Natsuki are nice and you're on their side. They earn their place in the story. That's about it, really, although granny's cool. However I really liked the way that the film's third act gives all the main leads their own crucial role in saving the day.

It's also very Japanese, from granny's estate to the hanafuda and the school baseball tournament. In a good way.

It's funny. It's exciting and heartwarming. The animation's fantastic. It's essentially a domestic story about a family get-together, despite the global threat of Love Machine, but if you're happy with that then I'd recommend it. (If you're not Tomoko...)