As the academy prepares for the Iga Festival, Shinobu and Lena discover a victim of a deadly Kouga technique, revealing a sinister plot to incite conflict between the ninja tribes. During the festival's traditional play, an entity known as Satan attempts to manipulate memories and spark a war, but Saizo and Shinobu's deep bond unlocks a hidden power. By uniting the Iga and Kouga lineages through love, they defeat the enemy and restore peace to their comrades.