For 28 years, Great Britain has been plagued by a horrific epidemic that turns infected people into insane, bloodthirsty zombies. Among the survivors in this post-apocalyptic world, several separate communities have formed, one of which is home to a boy trying to find a doctor for his dying mother. Together, they embark on a risky journey through the north of England, as beautiful as it is dangerous - the forests teeming with the infected.