Agata Katsuhira is a strange young man who doesn't feel pain. One day, he encounters a mysterious young woman named Sonozaki Noriko, who changes his life, as well as the lives of his classmates forever.

The Kiznaivers get to their training camp and are faced with the summer favorite, the test of bravery. Meanwhile, Chidori runs off on her own and the others realize that they might be connected by other means than just their pain.

The Kiznaivers all go their own ways. Meanwhile, Katsuhira finds out the truth about the Kizna Experiment and about Sonozaki's past.