The story is set in the "Dark Ages", a term referring to the time since Vandels appeared and started attacking humans. Beet is a boy who dreams of joining the "Zenon Warriors", a group of "Vandel Busters" who are considered to be the strongest on the continent. When the group comes to protect his village from the Vandel, Beltorze, Beet tries to join them but is rejected.
When Beltorze appears, the Zenon Warriors seem to have the upper hand until Beet cheers them on, causing the Vandel to notice his presence. Beltorze attacks Beet, and the Zenon Warriors are forced to break formation to help him. Beltorze uses that moment to attack again, which mortally wounds all of them. Hidden in the smoke, the Zenon Warriors decide to rescue Beet’s life by putting their life force into their “Saiga” and giving them to Beet. When Beet complains and asks them why they are doing this, it is revealed that Zenon is Beet’s brother. The now weaponless Zenon Warriors then emerge from the smoke and continue to attack Beltorze. When Beet regains consciousness, both Beltorze and the Zenon Warriors are gone. Guilt-ridden and sad, he cries and vows to destroy all the Vandels and end the Dark Ages. He then goes on a three-year training expedition.
His childhood friend, Poala, who Beet keeps impressing that she is going to marry him, later joins Beet and they form the “Beet Warriors”. As the story continues more is learned about the fight between the Zenon Warriors and Beltorze and the fantasy world of Beet is expanded on.
The manga series has been on hiatus since September 2006 because of Koji Inada's sickness.
