Kiki is a beautiful young woman who always dresses to expose her navel, but she harbors a secret frustration: she cannot derive any sexual pleasure from being touched anywhere on her body except for her belly button. This unusual condition is the doing of Nakaba, a junior from her middle school days, who inadvertently rewired her pleasure response to be centered exclusively on that single spot. Determined to break free from this strange affliction, Kiki decides to confront the source of her troubles. She tracks down Nakaba, who in the intervening years has transformed into a dedicated and eccentric belly button researcher. Her plan is not simply to ask for a cure but to get revenge by making him experience a humiliating defeat. However, her scheme backfires when she ends up being the one overwhelmed by the very sensations she sought to escape, as Nakaba uses his expertise to pleasure her belly button instead. The manga unfolds as an erotic romantic comedy that explores this unusual fetish, following the complex and awkward relationship between a woman cursed with a very specific erogenous zone and the man who created it and now studies it obsessively. The narrative is driven by Kiki’s conflicting feelings of resentment and vulnerability as she repeatedly fails to turn the tables on the earnest but oblivious researcher, leading to a series of intimate and comedic encounters centered on their bizarre connection.