Synopsis
In 2048, eight years after Charlene Roan's presidential election, the New Founding Fathers of America (NFFA) have regained control of the U.S. government and have re-instituted the annual Purge with its original rules. Racial supremacy and nativism have surged nationwide following their re-election, and many outside the ruling party are concerned that the upcoming Purge will inflict more damage on the country than the NFFA realizes. Married migrant couple Juan and Adela illegally cross the border into Texas to escape from a Mexican drug cartel and build a new life, with Juan working as a farmhand on the Tucker family ranch while Adela begins working near Austin.
Ten months later, on the eve of the next annual Purge, Juan and Adela join a migrant community behind a walled sanctuary with armed security to protect them. As the Purge begins, Adela witnesses a Purger group, who declare themselves to be a "Purge Purification Force" (PPF) that intend to kill those people that they consider non-American. The group passes by without hostility, and the migrant community survives the Purge with no incidents. Come morning, Juan and Adela return to their jobs, but both notice that many of their co-workers did not report to work. Shortly after, Adela is attacked by two Purgers but she is rescued by her boss Darius before both are arrested by police for killing their attackers.
Meanwhile, Juan and fellow migrant co-worker T.T. discover that the Tucker family has been taken hostage by their farmhands, who reveal themselves as Purgers intending to take the ranch for themselves. Ranch owner Caleb Tucker sacrifices himself and distracts the Purgers long enough for Juan and T.T. to rescue his son Dylan, Dylan's pregnant wife Cassie, and his sister Harper, who offer them a ride to search for Adela. Nationwide news struggles to understand why civilians continue to celebrate the Purge after its ending. The group rescue Adela and Darius after the police van carrying them is ambushed by more Purgers. Darius stays behind to search for his family while the others escape from a burning Austin. At a gas station, they hear news reports about chaos and destruction in all fifty American states, with local emergency services overwhelmed, in an event described as the "Forever Purge". To protect non-Purger civilians, Canada and Mexico have opened their borders for the next six hours, following which the borders will close and entry would be denied. The group decide to escape across the Mexican border through El Paso.
By the time the group arrives in a chaotic El Paso, the NFFA has condemned the Forever Purge after their politicians and representatives are targeted, and invokes martial law across the United States in an effort to contain the violence. In response, the Canadian and Mexican governments announce the early closure of its borders, leaving those who tried to cross it vulnerable to the Purgers. Fighting through El Paso, Adela and Cassie are split from the group by mili