Umi is a young woman from a remote, depopulated island who travels alone to Tokyo after her grandmother is hospitalized. Her only remaining family member, her grandmother is the reason she relocates, seeking work to support herself. She finds a live-in housekeeping job at what turns out to be the shared residence of the hugely popular male idol group RISE, a band she has secretly been a devoted fan of for years. The catch is that the group unknowingly hired her believing she was male, and she must keep her fan identity hidden at all costs or face immediate termination.

The story is set primarily in the group’s stylish Tokyo apartment, where Umi begins an intense, secret double life. By day, she serves as the dedicated housekeeper for the three members, each with a distinct personality. Hinata is the group’s charismatic center, publicly known as the "smiling prince" with a flawless, gentle image, but privately he is blunt, guarded, and initially treats Umi with cold suspicion due to past betrayals by fans. Izuki is the alluring, mischievous "sexy devil" who is overly friendly and playfully blurs boundaries, keeping Umi constantly off-balance. Kazama is the warm, gentle "sunshine" member, a natural peacemaker who is kind and perceptive from the start.

At first, the members are wary of Umi, viewing her as a potential scandal risk. However, her earnest, hardworking nature gradually wins them over. The central conflict emerges between Umi and Hinata. A major turning point occurs when Hinata collapses from overwork, and Umi nurses him back to health, leading to a rapid, deep connection. Umi begins to see Hinata not as an idol, but as a man, while Hinata’s cold exterior cracks, revealing growing romantic feelings he struggles to control.

The story explores the dangerous tension of their hidden relationship, which is constantly threatened by the gap between a national idol and a common fan. After Hinata finally confesses and they begin a secret relationship, they agree to meet only one day a week to avoid detection. The narrative arcs include Umi’s accidental outing as a fan, which nearly destroys her job and trust, a scandal when their photo is leaked online just before Hinata lands a major drama role, Umi’s self-imposed disappearance to protect his career, and the couple’s eventual reunion and decision to pursue their love cautiously but honestly. The series concludes with their relationship firmly established, navigating the ongoing challenges of fame and privacy.