When Henry Williamson wakes from surgery, he's paralyzed, alone and in the dark. Within hours, the hospital has been overrun by the victims of a new virus. They are gripped by a bloodthirsty, zombie-like rage, desperate to feed on the uninfected. With the help of a handful of the surviving medical staff, Henry must get on his feet, escape from the hospital and get across a countryside ravaged by the flesh-hungry walking corpses to find a way... any way to safety.