The gang of Mystery Inc. take a trip to Japan and find themselves circling Asia and the Pacific in a treasure hunt, racing against the vengeful Black Samurai and his Ninja warriors to find the legendary Sword of Fate, an ancient blade fabled to possess extraordinary supernatural powers.

At a time when nations are warring, a sword with mysterious power called “Heaven’s Sword” is stolen. The sword is said to give its wielder the power to conquer the world. Various ninja all over Dokutake Castle and beyond also manuevering for this sword of immense power. Rantaro and his classmates are assigned to retrieve the stolen sword, their first real ninja mission.

Although she’s only sixteen and looks even younger, Misao Makimachi is already a skilled and competent member of the Oniwabanshu ninja clan. That’s fortunate for Misao, because her onimitsu talents may be all that keeps her alive when a journey in search of the leader of the clan, Aoshi Shinomori, leads her instead into a face-to-face encounter with an even more dangerous man and a plot to overthrow the Meiji government! Quickly enmeshed in the affairs of the legendary assassin Hitokiri Battosai, now known as Kenshin Himura, wielder of the reverse-blade sword, Misao finds herself pulled into the middle of a deadly intrigue against Makoto Shishio, who is orchestrating the conquest of all Japan – beginning with Kyoto!