When a NASA space probe breaks up over Mexico, the extraterrestrial matter it is carrying leads to an alien infestation. With the northern half of the country quarantined, the US government builds a huge wall to prevent the enormous people-stomping beasties from crossing over the border.
American photojournalist Andrew Kaulder (McNairy) is on the scene to capture the aftermath of the incident, but his plans change when his wealthy boss orders him to get stranded daughter Samantha Wynden (Whitney Able) back to the US. Carefully making their way through the hazardous creature-ridden country, Andrew and Samantha grow closer as they attempt to return home alive.