Mamoru Hosada’s follow-up to his international hit Toki o Kakeru Shōjo/The Girl Who Leapt Through Time (2006) is once again a riotous mix of unlikely elements, blending high concept science fiction ideas with knockabout humour, romance and family drama. As in The Girl Who Leapt Through Time it’s an unlikely combination but it works remarkably well and helped to cement Hosada’s reputation – the inevitable comparisons to Hayao Miyazaki continued though, apart from a shared affinity for the Japanese countryside and a love of detailed and authentic characters, they’re very different directors.

The involved and absorbing plot of Summer Wars starts on a low-key note. Kenji Koiso (voiced by Ryunosuke Kamiki in the Japanese original and Michael Sinterniklaas in the English language version) is a gifted mathematics student at Kuonji High School and spends much of his spare time helping to moderate the massive virtual reality world OZ with his friend Takashi Sakuma (Ayumu Saito/J. Michael Tatum). One day, Kenji is invited by fellow student Natsuki Shinohara (Nanami Sakuraba/Brina Palencia) to join her at a family gathering to celebrate her great-grandmother Sakae Jinnouchi (Sumiko Fuji/Pam Dougherty)’s 90th birthday, not telling him until they get to the family home outside the city of Ueda that she’s planning to pass him off as her fiancé. The Natsuki clan are an odd bunch, descendants of a samurai who served the Takeda clan and friction becomes evident when computer genius Wabisuke Jinnouchi (Ayumu Saito/J. Michael Tatum), Natsuki’s half-great-uncle, turns up a decade after he fled to the States with family fortune. But Kenji and the family soon have bigger problems to contend with – Kenji cracks a mathematical code sent to him in an email and inadvertently activates Love Machine, a virtual artificial intelligence which uses Kenji’s phone and OZ avatar to hack the virtual reality, wreaking havoc as it goes. Kenji, Takashi and and Natsuki’s cousin Kazuma Ikezawa (Mitsuki Tanimura/Maxey Whitehead) try to stop the curiously named Love Machine but it absorbs millions of user accounts and starts interfering with the real world devices attached to the system, causing traffic jams and disabling electrical devices across the world. Things take an even more sinister turn when Love Machine (which we learn was developed by Wabisuke) turns off Sakae’s heart monitor, killing her and then threatens to crash the Arawashi Asteroid Probe into nuclear power plant…

Amid all the eye-wateringly beautiful cyberpunk imagery, madcap comedy and impending threat of Armageddon, Hosada is really interested in comparing and contrasting the organic and often dysfunctional familial network with the artificial virtual network of OZ. For all its complexity and the power unleashed with it by Love Machine, OZ is no match for the extended Jinnouchi clan who channel the sprit of their samurai ancestors, putting most of their differences aside to rally the troops and eventually defeat the malicious AI. Hosada unsurprisingly favours the real, tangible values of a family network over the fleeting and essentially meaningless “relationships” forged online (as such it’s an early critique of social media) – families may squabble, fall out and be hotbeds of ill-feeling and trauma but at their best they’ll pull together and save the day.

As with The Girl Who Leapt Through Time there’s not a great deal here that’s particularly new, but the way that Hosada stirs all the familiar ingredients together into a satisfyingly engrossing plot is often exhilarating and highly imaginative. The stuff in the virtual world of OZ is mind-bending and a little baffling at times with its warring avatars, account-eating AIs and blurring of lines between the real and the virtual but visually it’s quite extraordinary. The whole film is beautifully drawn and animated in the same style as The Girl Who Leapt Through Time and manages the same deft mix of charm, dazzling science fiction ideas and comedy even more seamlessly.

There’s a marvellous moment when granny, very much of the old school and firmly rooted in the real world, opens up her seemingly infinite contact book to start calling up family and friends in high places to get everyone pulling in the right direction as Love machine first starts to make its presence felt in the real world and the comedy runs the gamut from slapstick silliness to the inspired – commentators on a televised baseball game that one of the family is so absorbed in that she barely notices the potential catastrophe breaking out around her often seem to be commenting on those very same world events, an idea possibly inspired by a similar moment in Joseph Ruben’s Dreamscape (1984), itself partially set in a virtual world of dreams.

Where Hosada most resembles Miyazaki is their shared ability to populate their films with large casts of very believable characters. In Hosada’s films, they often start out as anime stereotypes (how many films have we seen – and will likely continue to see – about lovestruck high-schoolers?) but which then develop into nuanced and textured characters with depths one might not necessarily associate with animated films. The family members eccentricities are both funny and very real and if the film ends on a traditional upbeat anime note, then at least we’ve spent the rollercoaster journey getting there in the company of amiably daft characters that you really do start to care about, despite them being no more “real” than anything they encounter in OZ.

Summer Wars was a huge hit at the Japanese box office and met with high praise when from the critics when it made its way to the west who, like audiences before and after then, fell for its sophistication, with and sheer cleverness. It was the first Japanese animated film to win a coveted place on the program of the e Locarno International Film Festival in Switzerland where it was nominated for the Golden Leopard award in 2009 and it played at several other mainstream festivals, including Berlin  and the Japan media Arts Festival and deservedly took home the Gertie Award for Best Animated Feature Film at the Sitges Film Festival. It would be the last film that Hosada would mnake for the Madhouse production company before he set up Studio Chizu with his The Girl Who Leapt Through Time and Summer Wars Yuichiro Saito and together they would make several more acclaimed animated features – Okami Kodomo no Ame to Yuki/Wolf Children (2012), Bakemono no Ko/The Boy and the Beast (2015), Mirai no Mirai/Mirai (2018) and Ryu to Sobakasu no Hime/Belle (2021).