IN THE NEAR FUTURE, crime has been eradicated in the United States—except for 12 hours every year, when bloody hell breaks loose. That day, known as the "Purge," is a no-holds-barred bloodfest. Americans are encouraged by the government to loot, rape, and murder with impunity, as a means to keep violence at bay for the rest of the year. The haves lock themselves into their fortified McMansions, while the have-nots get beaten to pulps in dank alleyways. Thus sets the stage for writer/director James DeMonaco's tense little morality tale The Purge.

In this slice of dystopia, James (Ethan Hawke) sells high-end lockdown systems to the affluent, which keep the annual Purgers at bay. Cozy and smug in a gated community, his wife Mary (Lena Headey, AKA Cersei Lannister!) and their two kids seem a little dubious of the reactive holiday, casting sidelong eyes at the closed-captioned snuff films beamed into Americans' TVs during the Purge. But it is what it is, right? Until their sympathetic son lets a hunted homeless man into their "panic house" during the annual blood bath, and a gang of WASPy, mask-wearing boarding school psychopaths aims to smoke him out or kill the entire family in the process.

If it all sounds a little fraught and maybe a touch heavy-handed, I'm not going to spend too much time contradicting you. But it's also a pretty darned good, suspenseful, twisty bit of cinematic claustrophobia. The Purge is a home-invasion flick that's gory and sick and allegorical, blanketed in physical darkness, with a tinge of Bret Easton Ellis-esque American psychopathy for good measure. Even with its high concept, it sticks to a simple system of scare, menace, and bully, simultaneously making the audience a crowd of bloodthirsty Purgers while repulsing with its depictions of rich white people unleashing their inner beasts.