Exceedingly eager-to-please and ferociously intelligent, 10-year-old Melanie (Sennia Nanua) seems a prized pupil. Why is it then that she's kept under lock and key-and manacled for good measure-in a military bunker? A virulent viral outbreak has transformed this teacher's pet into a predator, ravenous for human flesh. But, unlike millions of other similarly afflicted "hungries," Melanie has retained her cognitive functions and thus become the subject of desperate scientific study. When a zombified horde lays siege to the compound, Melanie and her minders (Gemma Arterton, Glenn Close and Paddy Considine) escape into London's hungry-infested remains, where they must evade extinction at every turn.

In adapting Mike Carey's engrossing novel, TV veteran Colm McCarthy (Sherlock; The Tudors; Peaky Blinders) proves equally adept at post-apocalyptic spectacle and intimate drama, ensuring that the film's moral quandaries prove every bit as haunting as its indelible images. This is precisely the strain of astute speculative fiction that demands a sprawling canvas in order to explore its rich themes, including the unsettling acknowledgment that, regardless of our resilience and resourcefulness, there may be some horrors that are truly inescapable.