Nanami Takahashi falls for Motoharu Yano, the most popular, carefree boy in class. For Nanami, it's first love, but Yano is still grieving the death of his girlfriend who died the year before.

I know what Yano was like before he started going out with my sister...

And what he was like after she died.

How he held the tears back and looked as if he wanted to die...

I understand him a whole lot better than you.