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 kids are forced into doing self introductions... However, it appears that the self introductions that Sonozaki wants them to do requires much more than the usual name and what class they're in. They find out that every wrong answer has a penalty, and painfully learn that they are indeed connected to each other...

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.