Mihama Academy, a school set up by international organization CIRS to train the next generation of assassins, spies, and bodyguards using lost girls torn away from ordinary life by the myriad vicissitudes of fate, to be trained in the art of the gun. Among them are the four members of SORD, a special force set up to do the jobs the police and the army dare not touch: the pistol sharpshooter Rena, the sniper Tohka, the explosives and computer expert Chris, and the ninja spy Murasaki.