I did not see the original The Purge, but that doesn't appear to make any difference, since it's an entirely new story, with a completely different cast of characters. The central premise remains the same and is easily grasped: for 12 hours a year, all crime, up to and including murder, is legal. Those who can, barricade themselves in. Those who want, go out and wreak mischief on any and all unfortunate enough to cross their paths. The sequel focuses on three groups: a couple, Shane (Gilford) and Liz (Sanchez); a single mother Eva (Ejogo) and her daughter; and Leo (Grillo). The first two are innocent parties desperately seeking shelter, the third a grieving father, out to take revenge on the man who killed Leo's son in a drunk-driving incident, and got away with it. However, Leo is distracted from his task by finding himself (unwillingly) responsible for the safety of the other four, and shepherds them through a dangerous cityscape towards what should be safety. However, the night's events may not be such the free-for-all it seems, and the 1%'ers inside their safe compounds, want in on some of the murderous action too.
Which is where the film takes a right-turn in the final reel, shifting from straightforward urban action into something with an apparent political edge. While there have been hints at a "social cleansing" component earlier - the purge being something endured almost entirely by the poor - this now becomes explicit. It's odd, and not entirely successful, mostly because it's as subtle as a Facebook post on election day, from a friend with radically different political views and no sense of restraint. The earlier stages work better, being cleaner and simpler, with some memorable images, such as an eerily deserted street, interrupted suddenly by a burning bus rolling through the intersection. Things like that help build a creeping sense of unease, which is likely a good deal more effective than the blandly noisy carnage that ensues: the only shocking moment there, likely comes just when safety appears to have been secured. Home invasion still remains a more reliable way to push the fear button.