In a futuristic world known as Sand Land, the only river that fed the whole world has suddenly dried up and the only source of drinking water is in the possession of the king who does not hesitate to charge exorbitant prices. Demons and humans live together in this drought world until Sheriff Lao informs Beelzebub of the possible existence of a fountain, which could provide for both humans and demons. Beelzebub and his friend Thief decide to accompany him in search of this resource.