It is a testament to the power of music that a single song by glam-rockers T. Rex could inspire an epic sci-fi manga spanning 24 volumes that has now been transformed into an equally epic live-action movie trilogy, making it one of the most expensive movies to come out of Japan.

The film starts in 1973, when T. Rex were in their heyday, as young Kenji Endo and his friends wile away the long hot summer building a cubby house and fantasising about saving the world from super villains, while staying out of the way of the local bully twins. Their exploits are written down in a notebook that becomes "The Book of Prophecies".

Fast forward 30 years and the schoolboy friends have drifted apart, with most of them ending up as salarymen. Kenji is working in a local convenience store (although without falling to the depths of depravity and geekdom of Kevin Smith's CLERKS) with his family, while having to look after his baby niece since his sister disappeared. When a friend dies, another local family disappears, and a new religious cult appears, there is an uncanny resemblance to the events written in The Book of Prophecies. Kenji gathers his old school friends to try and find out who is behind the cult and the mysterious disappearances.

This first part is very much an origins story. For anyone not familiar with the manga, the film is fairly complete in itself so you won't be left wondering what is happening, but the ending is clearly set up for the sequel. In the second part, set in 2015, it is Kenji’s niece Kanna who takes over the lead as she battles Friend, the cult leader, by infiltrating the cult. In the third part, set two years later, Kanna is firmly established as the leader of the resistance as she enters into the climactic battle.

As with most anime, to fully appreciate this film does require some knowledge or understanding of Japanese culture, which means it will make a lot more sense to the anime fan boys than the average cinemagoer. However, even without understanding the subtle nuances of Japanese culture, there is plenty of humour and action, as well as real world references (such as the religious cult), to keep most sci-fi fans engrossed through its almost two-and-a-half-hour running time. And naturally, being Japanese, there is a giant robot trying to destroy the city (where was Dai-Nipponjin when they needed him?)

This is a complex story that needs a genuine commitment on the part of the viewer, running to a total of well over seven hours. The trilogy cost millions to make, but I couldn’t help thinking that it might have been better suited to being serialised into one-hour chunks for TV. Either way it is epic storytelling filled with interesting ideas, even if it doesn’t capture the full complexity of the original manga. In terms of extras, it is basically the same as came with the DVD of the first part, including the booklet.

20th Century Boys Trilogy is out now in a four-disc DVD set and is available from Play and all good retailers.