Sarah infiltrated the military base and rescued Wayne, barely making it out alive and discovering that Jack Glass and his forces are virtually unstoppable. But as Sarah and Wayne hide in the woods to lick their wounds, Ron has shown up on their doorstep, miraculously alive and well instead of the walking corpse he should have been. He shows Sarah the secret project hidden deep in the woods that his team of dedicated scientists has been working on for years. It's a chance to do the unthinkable: cure the zombie virus and turn every member of the undead back into their healthy, human form. Consigning Sarah to his team, they must race against the clock and gather the final pieces to complete the project before the enemy discovers them and wipes them out. But Glass's army is growing by the day and new intelligent zombies stalk their every move like a shadow. Sarah is forced to adapt the way she fights and face them head on if she ever wants to see the light of day again...