Agata Katsuhira es un joven extraño que no siente dolor. Un día, se encuentra con una misteriosa joven llamada Sonozaki Noriko, que cambia su vida y la de sus compañeros de clase para siempre.

Los niños se ven obligados a hacer presentaciones personales ... Sin embargo, parece que las presentaciones personales que Sonozaki quiere que hagan requieran mucho más que el nombre habitual y en qué clase están. Descubren que cada respuesta incorrecta tiene una penalización y dolorosamente aprendemos que de hecho están conectados entre sí...

Los niños descubren que en realidad hay otro Kiznaiver, y van a buscar esta figura misteriosa.

The kids get to know Hisomu and Sonozaki promises to let them know a secret about Kiznaivers if they agree to go to a summer training camp.

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.

Something from Honoka's past comes back to haunt her, and Nico makes another attempt at becoming her friend.

The Kiznaivers get stuck in a building during a typhoon and some hidden feelings start to come to light.

The Kiznaivers start to hear each others thoughts, which makes things even more complicated. Meanwhile, a secret about Sonozaki and Katsuhira is revealed.

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

Katsuhira finds out what happened to the friends from his childhood and Sonozaki is intent on making the Kizna Experiment successful no matter what.

Noriko attempts suicide by jumping off a bridge while black Gomorin share her pain with the entire city, in an effort to unite its citizens.