The story's protagonist, Narumi Takayuki aka Takoyaki (because of his cup), is an ordinary high school student, neither especially ambitious nor stressed out about his college plans. He meets Suzumiya Haruka in a bookstore, one year before her best friend Hayase Mitsuki sets them up in their third year of high school. The relationship progresses at a snail's pace while he is unsure about his feelings, but Haruka gradually wins him over, even inspiring him to try for a tougher university. One day, while he is unexpectedly delayed by Mitsuki on her birthday, Haruka is involved in an accident as she waits for him at a busy transit station. During this time, Mitsuki takes care of him and the two become intimate and co-dependent, as they feel merciful and come to terms with Haruka's accident.