Political filmmaking disguised as genre entertainment, this low-budget horror item is surprisingly serious in its consideration of class inequality and violent crime in the U.S. It takes place in a dystopian future where the government, hoping to exorcise criminal impulses in the populace, has instituted an annual holiday on which crime goes unpunished. Ethan Hawke plays a security firm executive who intends to spend the annual “purge” under lockdown with his wife and kids; when a homeless stranger sneaks in to escape a homicidal mob, the family is marked for death too. Writer-director James DeMonaco spends little time on exposition, jumping quickly into the suspense and barely letting up until the end. Emphasizing action over psychology, he makes it difficult to sympathize with any one character, which adds to the movie’s value as a provocation.