In a border town, Liora's younger brother falls ill with a strange disease, and the priest declares that the only way to obtain a cure is to marry Malachar—the demon king, who has been sealed away for a hundred years. Liora volunteers to become the sacrificial bride, steps through the gates of hell, and enters into a blood pact with the demon king. Within the royal palace, she uncovers the undercurrents of power struggle: the demon duke Leviathan covets the throne, while his maid Selene secretly warns him. A mark of the Fire God emerges in Liora's palm, and Malachar's attitude shifts abruptly—he may be the reincarnation of the ancient Fire God. Leviathan falsely accuses her of plotting a coup; during his exile, Malachar grows close to Liora and falls in love with her. In the ruins of the Fire God, she inherits divine authority, rallies oppressed tribes, and ultimately wages a decisive battle to overthrow the usurper, be crowned as the Queen of Hell, abolish the system of sacrifice, and ensure mutual prosperity between the human world and the underworld.
