Earth is the target of the former Sargasso prisoners who took over the prison asteroid and attack our planet. To counter this, Brave Seijin (Starman, more commonly alien) chose six (initially, only five; Geki joins later on) youngsters from Earth to receive the DagBraces and turn into Dagwon, the alien aequivalent to "brave". Rai, the seventh member of the team, is an alien officer who may possibly be the support Brave Seijin claimed there was no time to call upon when the invasion began. Because of this unfortune, Brave Seijin resorted to enlisting human beings to act as their own planet's defense.