In the dark century, people suffer under the tyranny of the Vandel, demons who can control monsters. Those who hunt these devils are called Vandel Busters, and the Zenon Squad is known as the strongest buster team on the continent. A young boy named Beet dreams of joining the Zenon Squad. But one day, due to Beet's mistake, the Zenon Squad is defeated by the devil Beltose. The five dying busters pour their life force into their five weapons, the Saiga, and entrust them to Beet before passing away. Years later, the young Vandel Buster Beet sets out on his journey to fulfill the Zenon Squad's will and put an end to the dark century.