Given the country's overcrowded prisons, the U.S. government allows for one night a year in which all crime, including murder, is legal for 12 hours. During one of these free-for-alls, a wealthy family is held hostage for harboring the target of a murderous syndicate.
Three groups of people left stranded in the streets on Purge Night, an annual night in which all crime is legal for 12 hours, find themselves working together to try and survive the chaos and violence that occurs.
Former Police Sergeant Leo Barnes becomes head of security for Senator Charlie Roan, a Presidential candidate who vows to eliminate the Purge. On the night of what should be the final Purge, a betrayal from within the government forces Barnes and Roan out onto the street where they must fight to survive the night.
America's third political party, the New Founding Fathers of America, comes to power and conducts a sociological experiment: no laws for 12 hours on Staten Island. No one has to stay on the island, but $5,000 is given to anyone who does.
During a 12-hour period when all crime - including murder - is legal, a group of seemingly unrelated characters cross paths in a city in an altered America ruled by a totalitarian political party. While the clock winds down, some will fight, some will hide, others will embrace what it means to purge to its fullest extent - whether for revenge, personal gain, protection, or unadulterated glee. As each character is forced to reckon with his or her past and plot how to better their futures, they soon discover how far they will go on Purge Night.
All the rules are broken as a sect of lawless marauders decides that the annual Purge does not stop at daybreak and instead should never end as they chase a group of immigrants they want to punish because of their harsh historical past.