As a nurse in the genetics department, Sarah witnesses the mutation of the AIDS vaccine. Instead of a cure, the vaccine turns into a viral curse, spreading rapidly and infecting patients. Now the dead walk the earth, and Sarah is the only hope for a small group of survivors. But zombies aren't the only threat. Winter is on the way and supplies are running low. Now it's up to Sarah to lead the group to warmer climates so they can survive. When a new threat reveals itself, they must fight for their lives one more time. Will anyone survive?