In THE PURGE, a future America has dealt with crime and unemployment by sanctioning an annual 12-hour period–The Purge–in which any and all criminal activity is legal (apparently, in this fictional world, crime is caused by violent impulses rather than chemical imbalance, drug addiction and poverty). A wealthy family prepares for the night, fortifying their home and hoping once again to wait it out. But a stranger comes knocking, desperate for help, and he’s not alone. He’s pursued by a gang of thugs who want him back at any cost.
Love the background concept, although the basic plot execution looks like any other “normal family under siege by psychos” film that’s come out in the last few years.
(What would be interesting is if the people outside told the family the man they’re harboring is actually an evil criminal–say, a murderer who killed their children during past Purges–and that’s why they’re after him. The man disappears inside the house, and now the family must contend with a murderous intruder lose on the premises while trying to keep the invaders out. After a while, they start to enjoy the cat and mouse, as they, like everyone else, is subject to the same violent impulses.)