During his second year of high school, Haruto Otsuki decides to start a part-time job in housekeeping to fill his summer vacation. His first assignment brings him to the home of Ayaka Tojo, the most beautiful and popular girl in his school, a classmate he has never spoken to before. While Ayaka maintains a perfect and untouchable image on campus, Haruto is surprised to discover that she is a complete slob at home, unable to keep her living space clean or organized.

Despite his initial bewilderment, Haruto diligently applies the housekeeping skills he learned from his grandmother, who raised him after his parents were killed in a car accident. As he cleans the Tojo residence and prepares home-cooked meals, his earnest nature and work ethic endear him to Ayaka's family. Her younger brother, Ryota, quickly becomes attached to Haruto, and even her parents, both busy company executives, grow fond of the reliable young man.

The story primarily unfolds within the Tojo family home and at their high school. Through the intimate setting of the housekeeping job, Haruto and Ayaka begin to share special moments outside of school, such as going grocery shopping together and attending shy movie dates. As they spend more time together, the distance between them shrinks, and Ayaka finds herself drawn to Haruto's personality and quiet competence, while he gets to know the vulnerable and messy girl behind the school idol facade.

Notable narrative arcs include Haruto winning over the skeptical members of Ayaka's family, the pair navigating their awkward but growing feelings for each other, and their relationship progressing from a simple client-and-worker dynamic to something much more personal. Other key characters include Haruto's best friend Tomoya Akagi, who is wasteful with his money, Ayaka's childhood friend and confidant Saki Aizawa, and Haruto's junior at the karate dojo, his childhood friend Shizuku Dōjima.