In a distant future, Earth lies devastated by war, reduced to a desolate wasteland where water, the most precious resource, is monopolized by a tyrannical king. Sheriff Rao, desperate to find a legendary lake, seeks aid from the demon king. Instead, he's granted the assistance of Beelzebub, the demon king's son, and his cunning companion, Thief.
Bound by circumstance, this unlikely trio embarks on a perilous journey across the unforgiving desert, confronting dragons, bandits, and the formidable might of the King's army in their quest for survival and justice.