Six years after a NASA probe crashed in Mexico, extraterrestrial life forms have begun to inhabit an area now known as the Infected Zone. The US and Mexican militaries have struggled to contain the creatures, leading to the construction of a massive wall along the US border and ongoing military action within the zone. Amidst this backdrop, a jaded American photojournalist, Andrew Kaulder, is tasked with safely escorting his employer's shaken and distressed daughter, Samantha Wynden, back to the United States. Initially self-centered and disinterested, Andrew is burdened by the responsibility but motivated by the potential financial and professional rewards of ensuring Samantha's safe return.

Their journey is fraught with danger and unpredictability as they attempt to travel by train, boat, and on foot to reach the American border. The pair encounter not just the creatures, but also the devastated human lives left in their wake. Along the way, they must contend with the military presence as well as local populations living in fear and uncertainty. Through their travels, the alien-infested landscape of Mexico serves not only as a perilous backdrop but also as a canvas reflecting humanity's own struggles and resilience. Their evolving relationship, tested by adversity and the shared experience of a world turned upside down, offers a glimmer of human connection in contrast to the chaotic and unpredictable world that the monsters have wrought.