Humanity was defeated by their natural predator, Dragons, who prey on humans. Mankind fled underground, fearing the surface as a "World of Death." The 6th Food Procurement Squad, while exploring underground, encounters a boy from the surface named Shiyu. Immediately after, a Dragon attacks. Facing overwhelming power, everyone prepared for total annihilation. But the boy smiles ── "A delicious-looking one has arrived." The predatory competition fantasy between dragons and humans begins.