Ninjutsu school teacher Doi Hansuke goes missing after heading to a duel where he was challenged by Tasogaredoki Ninja Moroizumi Sonnamon.

Denzo Yamada and Tamatsu, a sixth-year student, hear about the situation and begin searching for the missing Doi.

Meanwhile, information comes in that there have been some disturbing movements at Dotake Castle, which has always been an enemy of the Ninjutsu Academy.