Synopsis
430 years ago in the ninja village of Iga, faction lead by Sandayu Momochi (Asao Uchida) and faction lead by Nagato Fujibayashi (Tetsuro Sagawa) were vying for superior position. Lower level ninjas called Genin were treated very poorly during this time, ruled by ninja "law" that no one knows its content. During this time a boy named Watari (Yoshinobu Kaneko), and his father Shikanme (Tokichi Maki) appeared in Momochi's camp. He becomes friends with Kazura (Toshitaka Kato) who runs training camp for genin. Watari requests Kazura to stop running the camp because he believed the reason for genin being treated poorly was because there were abundant supply of them being trained in this camp. Watari also recognized that behind this training camp was the ninja's "law". Momochi's vice leader Otowa no Jyoto (Ryutaro Ootomo) orders his men to go to Takeda's fortress Samidare. But it was a trap set for them, and they all perish in the attempt. In order to investigate the plot behind the killing, Watari sneaks into Fujibayashi's fortress. He battles Tateoka no Dojun (Toshi Amazu) with his "oboro no Jyutsu" a ninpo that projects multiple images of himself, and succeeds in escape. Kazura has a sister named Tsuyuki (Chiyoko Honma). She was in love with Shindo no Kojiro (Kunio Murai), but they felt that the only way to wed is to flee from Iga and become nukenin - an escapee ninja. Momochi who discovered them tells them if they can infiltrate fort Samidare and assassinate its lord, he will grant them their marriage. But this was also a trap to kill them both. What was waiting for them are six ninjas, and both Tsuyuki and Kojiro is killed by them. Kazura who found out about Tsuyuki's mission goes after her to fort Samidare, but gets caught. Watari also follows Kazura and kills two of the six ninjas Shijima (Akio Wakinaka) and Yosame (Daisuke Awaji) and rescues Kazura, but is met by Toriko (Kensaku Hara) and is nearly defeated. Shikanme shows up and together they defeat Toriko. They also defeat Tsubuki (Chiyo Okada) and Kugutsume (Masaru Ooshiro), and eradicates all six ninjas at fort Samidare. Kazura in order to avenge his sister's death sneaks into Fujibayashi's fortress, and blows it up along with himself. Kojiro who was thought to have died was rescued by Shikanme. He figures That Dojun and Otowa no Jyoto are one and the same person. Dojun together with Momochi intended to split Iga clan in half so it would be easier for them to rule the clan.