"I've got a big story to tell," says the narrator in the first chapter of Oblivion. "The end of the world … and stories don't get any bigger than that."
The fifth and final book in Anthony Horowitz's Power of Five series is indeed epic: the most ambitious he's yet written. Grander and bleaker than the Alex Ryder novels with which he made his name, it's about the Five: a group of supernaturally gifted teenagers who must save the world from ancient forces of evil known as the Old Ones.
It opens with the Five scattered across the planet and hurled 10 years forwards in time, into a world dominated by the Old Ones and the humans who serve them. They must somehow make their way back to each other, for only together can they prevail. The story is simple: each one must overcome obstacles, travelling through a world of appalling devastation in which almost every contemporary anxiety has comes to pass.
The scale of the apocalypse is memorably conveyed with a wonderful sleight of hand: a description of a filthy city of starving beggars that seems to be some third world crisis zone, but turns out to be New York. Horowitz describes famine in the US, plague in China, terrorist bombs in Britain. All infrastructure has been destroyed. We get some chilling glimpses of the aftermath: corpses rotting in a tube train; a prim Home Counties village where cannibalism has taken over. Perhaps most powerful of all is a sequence of Mount Vesuvius erupting, which brings to mind the paintings of John Martin.
Behind all this lies a sense of moral outrage at a world that allowed climate change, rainforest destruction, massive inequalities.
There's a fierce political urgency here, touching on everything from the Arab spring to the eurozone crisis, giving the book a topical, timely feel. Of course, Horowitz is hardly alone in this. Dystopian fiction has dominated young adult publishing since The Hunger Games, and he seems to acknowledge this by making one of his characters handy with a bow and arrow. As in most such fiction, the only hope comes from youth. Oblivion's teenage protagonists are repeatedly patronised and underestimated, yet they alone can save the Earth from the Old Ones and humanity from itself.
This is an empowering message, and it's underpinned by an ethical system that opposes selfishness with self-sacrifice. Yet the book's moral and political ambitions are undercut by Horowitz's tendency to depict his human villains as grotesques, often characterising them by physical imperfections, heavily accented English, or effeminacy. In the Alex Ryder stories, this strategy followed the classic Bond villain formula, but in Oblivion, it feels tonally wrong. Descriptions such as "weedy", "girlish" and "piggy eyes" are jarringly out of place in a book of such gravity. It is also unfortunate that while Horowitz is careful to show a mix of good and bad characters in most parts of the world, the Arab characters seem to be either self-serving or treacherous at best.
It's a shame that Horowitz allows such flaws to undermine his book's moral complexity, and its otherwise well-crafted consistency. For all its length, Oblivion maintains a propulsive momentum, powered by his trademark storytelling virtues: relentlessly piling on action, building suspense, teasing the reader with tantalising cliffhangers. Whether he fully achieves his deeper ambitions or not, it's exciting to see so big and bold a book being written for a young audience, who will find much here to think about, and much to enjoy.
• SF Said's The Outlaw Varjak Paw is published by David Fickling Books.
