Reign of Fire presents a bleak, 2020 vision of Earth where humanity has been driven to the brink of extinction by the accidental awakening of prehistoric, fire-breathing dragons. The world is depicted as a charred wasteland, with the remnants of civilization huddled in isolated, low-tech fortresses. By the film's primary setting of 2020, global infrastructure has completely collapsed, leaving survivors to scavenge for food and fuel while dodging aerial predators that have replaced humans at the top of the food chain.

Societal dynamics are defined by medieval survivalism blended with decaying 21st-century technology. The film explores a divergence from our timeline starting in 2002, where the rapid proliferation of dragons led to a global firestorm and the failure of all modern military superpowers. On Earth, the environment is characterized by a permanent 'nuclear winter' effect caused by ash and soot, rendering traditional agriculture nearly impossible and forcing a reliance on dwindling stockpiles and desperate communal living.

While the film's central premise is fantasy, it offers interesting parallels to real-world anxieties regarding ecological collapse and rapid species dominance. Its depiction of 2020 failed to predict the digital revolution, instead focusing on a regression of technology where hardware like the Harrier Jump Jet remains the pinnacle of utility. The film accurately captures the geopolitical tension between isolationist survival and aggressive interventionism, though its vision of 2020 as a literal ash-heap remains a stark contrast to the actual technological and social complexities of the decade.