Six years ago, NASA launched a probe to collect possible samples of alien life within our solar system. On re-entry, the probe crashed in Central America and soon afterwards new life forms began to appear. Now, half of Mexico is quarantined as an Infected Zone and the military struggles to contain giant creatures – but Whitney Able is lost in the Infected Zone and journalist Scoot McNairy has grudgingly agreed to find her and escort her to the safety of the US border.