Set at some point after the planet's gone bollock shaped, the film opens with some children who appear to be prisoners being taken from their cells to a class room where they are restrained at their desks while they taught all the usual school stuff.
Turns out that they're all infected by a semi-dormant virus which turns them into flesh eating rage-loonies when they come close to the uninfected.
The adults that control the day-to-day lives of the children are divided between those who want to save them, those who want to slice them open to find a cure and those who would be happiest putting a bullet in them.
One of the kids, the girl of the title, seems a lot more human and aware of her condition than the others. She bonds with the kindly teacher, seems to show an unusually deep curiosity of the world that isn't shared by her fellow infected and displays a wisdom that puts some of the less trusting adults on edge.
I'm probably not giving away too much when I say that at some point in the film the shit hits the window and the surviving humans have to decide if they wanna chance it on their own or put their trust in the strange child who's half zombie.
If you enjoyed 28 Days Later or The Last Of Us, this'll be right up your street. The acting is superb, the film's well paced and exciting, the script is excellent. Definitely one of the films of the year, and Paddy Consindine manages to deliver one word of dialogue to greater comic effect than most comedies I've seen for a long time.
Although the ending's a bit pony.