A couple are driving home when their car breaks down just as the Purge commences. Meanwhile, a police sergeant goes out into the streets to get revenge on the man who killed his son, and a mother and daughter run from their home after assailants destroy it. The five people meet up as they attempt to survive the night in Los Angeles.

How far would you go to protect your family? Keller Dover is facing every parent's worst nightmare. His six-year-old daughter, Anna, is missing, together with her young friend, Joy, and as minutes turn to hours, panic sets in. The only lead is a dilapidated RV that had earlier been parked on their street. Heading the investigation, Detective Loki arrests its driver, Alex Jones, but a lack of evidence forces his release. As the police pursue multiple leads and pressure mounts, knowing his child's...