During the grim age, humanity suffers beneath the tyrant Vandel, a demon who commands monsters. Hunters called Vandel Busters oppose him; among them the Zenon Squad is famed as the continent"s mightiest. A hopeful youth named Beet yearns to join that elite group. Yet one day, because of Beet"s mistake, the Zenon Squad falls to the demon Beltose. The five dying members poured their life force into their weapons, the Saiga, and then handed them to Beet before dying. Decades later, Beet, now a seasoned Vandel Buster, sets out to fulfill the Zenon Squad"s mission and bring an end to this dark era. His quest will push him beyond courage, unite forgotten allies, and strike at the heart of Vandel"s dominion to reclaim a world cloaked in perpetual night again.