Ken Ishikawa, who says he was "strongly influenced by Sanpei Shirato's ``Ninja Bugeicho'' and aspired to become a manga artist," is based on Ushijiro's original story about a baby saved by Fuma Kotaro. A masterpiece historical action drama that takes on the historical scenario of aiming for Ieyasu's head. In 1590, a ninja ran through the mountains of Hakone, evading his pursuers. His name is Fuma Kotaro. Kotaro receives an order from Hojo Ujimasa to safely give birth to a baby, the last bloodline member of the Hojo family, and raise him. ) succeeded in rescuing the baby from the womb. 17 years later, the baby Fuma Kotaro, who has grown up as a full-fledged ninja under Kotaro, is determined to overthrow Ieyasu Tokugawa, and engages in a brutal battle with the Hattori Nine Ninjas who protect Ieyasu. Throw yourself into it!!