In 2014, the New Founding Fathers of America, a totalitarian political party portraying themselves as successors to the Founding Fathers of the United States, are voted into office following an economic collapse and pass the 28th Amendment which sanctions an annual national civic tradition called "The Purge," the first of which takes place in 2017. The Purge occurs for 12 hours, from 7 p.m. March 21 to 7 a.m. March 22, during which all crime is legal and all police, fire, and medical emergency services remain unavailable. Restrictions prohibit government officials "ranking 10" from being disturbed, as well as the use of all weapons above Class 4 (explosive devices such as grenades, rocket launchers, and bazookas). Violation of Purge rules results in a summary execution by hanging. The Purge has resulted in unemployment rates plummeting to 1%, low crime, and a strong economy.
On March 21, 2022, James Sandin (Ethan Hawke), a top salesman for elaborate security systems designed specifically for Purge Night, returns to his home in an affluent Los Angeles gated community to wait out the night with his wife, Mary (Lena Headey), and their two children, Zoey (Adelaide Kane) and Charlie (Max Burkholder). The family is assured that the security system manufactured by James' company will keep them safe. Their neighbors attribute the size and fittings of the newly extended Sandins' house to his success in selling security products to them for Purge Night.
While the family awaits the start of the Purge, Zoey meets her boyfriend Henry (Tony Oller), an older boy whom James dislikes. James enables the security system, and as the Purge begins, the family disperses in their home to go about their normal routines.
Zoey returns to her room to unexpectedly find Henry, who managed to sneak back in before the security system was engaged, and says that he plans to confront her dad about their relationship. Meanwhile, Charlie watches the security monitors, and sees a wounded man (Edwin Hodge) calling for help. He temporarily disables the system to allow the man into the house. James races to re-engage the system and holds the man at gunpoint as Henry comes downstairs and pulls a gun on James. Henry fires at James and misses, but James fires back, mortally wounding and eventually killing Henry. During the chaos, the wounded man disappears and hides. James takes Mary and Charlie back to the security control room.
As James reprimands Charlie for letting the man into their home, they look over the surveillance cameras, where they witness a gang of masked young adults armed with guns, axes, and hammers arriving at the front lawn. Their leader (Rhys Wakefield) unmasks himself, compliments the Sandins on their support of the Purge, and then tells them that if they fail to surrender the man, they will be forced to "release the beast," implying they will forcefully enter the house and kill everyone inside. Mary asks James if the security system will help protect them, but James admits the system is essentially a security theater—it is only supposed to discourage potential invaders and would not actually protect them against heavy force. They decide to find the man and give him to the Purge gang outside, but after capturing the man, they realize they are no better than the gang waiting outside. They decide to spare the man, and defend themselves against the gang.
With their deadline having passed, the gang uses a truck to rip the metal plating off the front door, and enter the house. James fights back with a shotgun and kills several gang members before being mortally wounded by the gang leader. Charlie views the surveillance cameras, and notices their neighbors leaving their homes. The neighbors overpower and murder the gang. Elsewhere, Mary is subdued by two Purgers, one of whom tickle tortures her before almost killing her, but are both killed by the neighbors. As the gang leader prepares to kill the remaining Sandins, Zoey appears and kills him.
Mary thanks their neighbors for their support, but one of them, Grace Ferrin (Arija Bareikis), reveals their hatred for the Sandins due to the wealth acquired at their expense. They tie Mary, Charlie, and Zoey up with duct tape, pulling them out into the hallway to kill them. But as the neighbors make final preparations for the murder, the man re-appears, kills a neighbor (Tom Yi) with a Browning Hi-Power and holds Grace hostage, forcing the neighbors to free the Sandins. He asks if Mary wishes to kill the neighbors, but Mary spares them. Eventually, the sirens go off, announcing the end of the Annual Purge. The neighbors leave, and Mary thanks the man for his help, which he appreciates and bids the Sandins farewell.
News reports later state that this year's Purge is the most successful to date.
- Ethan Hawke as James Sandin
- Lena Headey as Mary Sandin
- Adelaide Kane as Zoey Sandin
- Max Burkholder as Charlie Sandin
- Arija Bareikis as Grace Ferrin
- Dana Bunch as Mr. Ferrin
- Chris Mulkey as Mr. Halverson
- Tisha French as Mrs. Halverson
- Tom Yi as Mr. Cali
- Rhys Wakefield as Purge gang leader
- John Weselcouch as Interrupting Purger
- Alicia Vela-Bailey as Female Tickling Purger
- Aaron Kuban as Purger
- Boima Blake as Purger
- Nathan Clarkson as Purger
- Chester Lockhart as Purger
- Tyler Osterkamp as Purger
- RJ Wolfe as Purger
- Trazariah Shells as Purger
- Edwin Hodge as The Stranger
- Cindy Robinson as Purge Announcement Voice
- Tony Oller as Henry
- Karen Strassman as Newscaster
- Peter Bzovdas as Dr. Peter Buynak