Upon moving into a new apartment building, Yui Hanasaka follows customary etiquette by introducing herself to her neighbor. Upon discovering that he is an upperclassman at the university she plans to attend, she requests assistance for her entrance exams. In another part of Tokyo, Natsuki Momohara visits her brother who resides in his own apartment. Meanwhile, aspiring singer Moka Aoshima reunites with her childhood friend, a budding novelist. Though separate, the three stories share a common thread: a predetermined fate will connect those with similar destinies, even in the confines of a single apartment room.