Following a standard raid, rookie sky pirate Coud uncovers a highly unusual cargo in his crew's hold: Ren, an "Edel Reid," a race valued by humans for bestowing special combat abilities on their partners via "Reacting." He soon realizes, however, that Ren is even more valuable than he anticipated. The pirate vessel is approached by three agents of the Edel Reid Complete Protection Agency "Arc Aire," who attempt to buy her. When Coud declines, the ship is abruptly assaulted by an unknown force, and Coud's captain tasks him with safeguarding Ren.