During her freshman year of high school, she discovered a boy was stalking her. Soon after, when she received a death threat in the mail, she went to the Usui brothers for advice. As a result of their suggestions, she decided to go buy some self-protection equipment. ~! Switch, who had been acting strangely, opted not to go and instead she went with Masafumi. Some time after they went out, they encountered Sawa's supposed friend Yukino - who stabbed Masafumi in the chest. As a result of a conversation with Switch, Yukino believed Masafumi was Sawa's boyfriend and acted out of revenge for her own ex-boyfriend dumping her in favor of pursuing Sawa. Shortly after Masafumi's death and his brother's subsequent downward spiral, Sawa and her family moved. She couldn't remain in the same town any longer, as it held too many memories and she kept seeing Masafumi wherever she went.
