Haru Aoyama and Kaede Kagaya have been friends since they were four years old, when they began living next door to each other. They are now 24 years old and still live in the same apartments. Kaede has held feelings for Haru for the past 20 years, but Haru doesn't seem to realize her feelings for him. She talks about this situation with her childhood friends Iori Hasumi and Mio Kotomori and decides to give up on her feelings for Haru. However, it's not easy for Kaede to disconnect her feelings for him. Meanwhile, Iori has liked Kaede since he was an elementary school student. He approaches her. Seeing this, Haru becomes disturbed. In fact, he made a promise with Kaede's late mother and he is honoring it.
