Traveling merchants have been attacked by vicious robbers. Wasabi, Namida, and Tsubaki of Team 15 are sent to the site of the incident to investigate. Tsubaki finds a clue that seems to point to samurai from her homeland, the Land of Iron. Furthermore, the clue belongs to a certain person that makes Tsubaki tremble in fear. That person is someone that she respected long ago, a fellow apprentice with whom she trained and honed her swordsmanship with—someone with whom Tsubaki shares a certain fate!