While being assaulted, he is saved by a mysterious girl. The next day, a transferred student is introduced to the class, which is none other than the mysterious girl named
Nagisa. The protagonist gets closer to her for the thank you and, by the way, they get closer, he learns that in fact they are childhood friends and finally go out together.
Only one day, the protagonist notices that his aggressors no longer annoy him, that Nagisa acts oddly, she looks unhappy as if she were going to cry every time their eyes crossed. He finds that the situation becomes to be strange...
(spoiler hidden)