Naomi Armitage and Ross Sylibus have changed their names and live with their daughter Yoko as a happy and normal family on Mars — until an android riot breaks out at an anti-matter plant on Earth.

The battle for the Capital city of Kyo rages as warring political factions vie for power against hereditary rulers. After the murder of her parents at the hands of her seditious uncle, a young girl named Kintoki flees to the mountains to lead a harsh life; she is renamed Kai Doh Maru by the local villagers. Rescued by Raiko, the Captain of 'The Four Knights' - honorable defenders who protect the peace of the city, she is raised within their group as a boy. Living among the Knights, she learns the practices of martial arts and develops into a skillful samurai, becoming a permanent member of their team. Now, as a young woman of seventeen, she begins to discover new feelings of passion and love for Raiko... but she also discovers that these new emotions cause a storm of jealousy and rage in another woman linked to her past.

A message has arrived from Kid the Phantom Thief, that he will steal a Japanese sword belonging to wealthy Onoe Family in Hakodate, Hokkaido. Conan and Heiji Hattori, who happened to be in Hakodate, are on the case to capture Kid. Coincidentally the family lawyer of Onoe is found murdered in the warehouse district, apparently slaughtered by a Japanese sword. The suspect is an investor/arms dealer who is said to be after Onoe family’s hidden treasure. In the North among cherry blossoms, the exciting hunt for treasure begins!