Although Yui is an engineer major without a girlfriend and has yet to develop feelings for anyone, he has formed a texting friendship with MIKI after receiving a wrongly addressed message. As Yui regularly texts MIKI, he notices Juji - a highly popular student who attends the same school. When Yui glimpses Juji changing his expression to happiness while sending a text, it triggers a sense of empathy within Yui's heart.