During the Warring States period in Japan, ninja groups belonging to different warlords were also engaged in power struggles in the shadows. One night, under a clear sky, Iga ninja Yamata (played by Masei Yoshino), Jin'nai (played by Shushi Kashiwabara), and Mouse were on a reconnaissance mission when they unexpectedly encountered their rivals. During this encounter, a huge fireball suddenly floated across the sky, surprising everyone. After returning to their village, under the leader's orders, they headed back into the forest to investigate the truth behind the fireball. Along the way, they encountered Rinrin (played by Mika Eji), who belonged to the same faction, and her companions, and they continued together. As a result, in the dense forest, the Iga ninjas were attacked by an unknown creature. The adversary was agile and had tremendous killing power, leading to the ninjas suffering casualties one after the other. Although Yamata, Jin'nai, and Rinrin managed to escape by chance, they were unaware that extraterrestrial beings were breeding rampantly. In an instant, the Iga village was ravaged, and Yamata and the others faced unprecedented challenges...