It is the dark century and the people are suffering under the rule of the devil, Vandel, who is able to manipulate monsters. The Vandel Busters are a group of people who hunt these devils, and among them, the Zenon Squad is known to be the strongest busters on the continent. A young boy, Beet, dreams of joining the Zenon Squad. However, one day, as a result of Beet's fault, the Zenon squad was defeated by the devil, Beltose. The five dying busters sacrificed their life power into their five weapons, Saiga. After giving their weapons to Beet, they passed away. Years have passed since then and the young Vandel Buster, Beet, begins his adventure to carry out the Zenon Squad's will to put an end to the dark century.

Sometime in the distant future, mankind is forced to live in domed cities while the rest of the world is left to recover from years of environmental hardships. In the Siberian Dome-polis, professional gamer Gainer Sanga and mercenary Gain Bijou commandeer an Overman and lead a mass exodus out of the city.

Hagiwara Mio is a 14-year-old TV actress who has gotten popular. One day on a set, she meets Kumagai Ichiya, who tells her that her acting "stinks." Mio is hurt by his comments, but she finds that she can't get Ichiya out of her mind. It turns out that Ichiya is a promising director, who directed a music video for Mio's friend Sawaki Aya, an idol singer. After the success of this music video, Ichiya is asked to direct a movie, and he wants Mio to be the heroine, because he feels that she is a "handsome" girl like the actresses of old. How will Mio cope with her feelings toward Ichiya?

The story is set in the future on the planet named Amoi which is controlled by a supercomputer named Jupiter. Among the mostly male human population, the light-haired elite class is allowed to temporarily keep the dark-haired "mongrels" as pets. One elite member, Iason, encounters a mongrel named Riki in the slums and decides to take him in. However, Iason keeps Riki longer than it is socially approved, and rumors abound about their possible relationship.