A kunoichi on the run, Kurenai Aria is a practitioner of Sakura style ninjustu. She fights to stop her clan from acquiring and misusing the legendary sword, Soul Edge. Her recent investigations have led her to befriend a young knight named Nicholi, whose captain and also seems to be hunting for Soul Edge to awaken some unknown power. With mutual goals, the two set out to stop the evil blade, once and for all.