Every day, Naoto Hachiouji is teased relentlessly by Hayase Nagatoro, a first year student he meets one day in the library while working on his manga. After reading his story and seeing his awkward demeanor, she decides from that moment on to toy with him, even calling him "Senpai" in lieu of using his real name. At first, Nagatoro's relentless antics are more bothersome than anything and leave him feeling embarrassed, as he is forced to cater to her whims. However, as they spend more time together, a strange sort of friendship develops between them, and Naoto finds that life with Nagatoro can even be fun. But one thing's for sure: his days will never be dull again.

Hayase Nagatoro and Naoto Hachiouji have grown closer: the girl spends more time than ever in the art club room with her senpai. Although he is always on edge, Naoto no longer seems to mind Nagatoro's presence. Time and again, Naoto demonstrates his hidden, cool demeanor, and Nagatoro displays her possessive tendencies. However, they still can not seem to completely close the distance between them. It is clear to everyone else that the pair have feelings for each other. For Nagatoro, there is nothing more entertaining than toying with Naoto. But as the girl shows no plans to stop teasing her senpai, it is only a matter of time before they realize how they truly feel.