The game's plot involves the heroes moving through various locations — space, urban environments, elaborate ruins — and fighting alien invaders. Bo Emperor Bill (Botei-biru, a pun of bodibil, a short of bodybuild in Japanese), the man who achieved ten consecutive victories in the Great Galaxy Bodybuilding contest, faces an ever decreasing supply of protein. He unilaterally invades neighboring star systems, in order to establish protein factories to replenish his supply. Feeling threatened, the heaven realm sent Idaten and Benten to vanquish Bo Emperor Bill. Thus the sweaty hot battle between the muscle brothers (aniki) and Builders Army begins.
