The true story that went on to inspire the creation of The Purgefranchise helps to underline just what makes the five-movie series so scary. Starting with the release of the first low-budget thriller in 2013, The Purge eventually grew into a much larger franchise with its own complex lore. The simple premise behind the franchise is that a semi-dystopian version of the United States allows its citizens to commit whatever crimes they want for one night only, and that's the backdrop for social commentary. Unlike other horror films, The Purge is distinctly human.