The setting for the narrative unfolds on a distant planet, 100 years ahead in time, just before Lisa and Lorna became members of the eX-D faction. The vehicle culture is composed of computerized, electric "AI cars" that operate on autopilot directed toward the desired destination. Unfortunately, one of these cars begins to exhibit erratic behavior. As leading operators for eX-D, Nina and Rei must uncover the treacherous machinations behind the rogue AI car, which has set a perilous course for them.