As Rentarou seems to be in a hopeless situation, Iroha arrives and shoots at the snake ninpou, freeing her brother. She tells him to get to safety and leave this to her. But Yaminin shoots at Iroha and she falls to the ground. Yaminin, however, decides not to kill Iroha and wants to take her as a trophy instead.
Rentarou uses substitution ninpou to escape the shurikens that come flying from a mysterious person behind the trees. Just then, Iroha finds him and wraps her arms around her crush. She says she is definitely getting his LINE. But Rentarou again uses ninpou to slip away, much to Iroha’s annoyance.
In the year 2022, due to continuing harm to the environment, the Ninja Act requires the public to undergo ninja training in order to harness power that can be used to produce fire, water and other natural energies.
Niji no Hebi leader Amakusa Shirou Tokisada has taken over Konjou Company and captured Rentarou’s sister Iroha. Unfortunately, Rentarou has used up all his shinobi power trying to force his way into the castle to save her.