In a distant future, where monsters freely roam and people rely on advanced technology and cybernetic horses, a quiet village grapples with monster attacks under the oppressive reign of Count Magnus Lee, an ancient vampire lord. When a young girl becomes the Count's victim, she turns to D, a mysterious wanderer renowned as one of the greatest vampire hunters. Determined to free the land from the Count's tyranny, D faces a perilous journey battling the Count's minions to end his centuries-old rule.