Eita Akutsu is a reserved high school boy with a deep passion for mechanics and robotics who lives a quiet, solitary life. From a distance, he harbors an intense crush on Makina Agatsuma, the school's beloved and seemingly unapproachable idol. His perception of reality shatters when Makina suddenly appears at his doorstep, injured and seeking his help. She reveals herself to be an advanced, lifelike android, specifically a "sexaroid" designed for intimate purposes, and she requires Eita's technical skills for repairs. Following this incident, Makina loses her previous housing and decides to move in with Eita, forcing him to navigate the chaotic reality of sharing a home with the girl of his dreams, who is not only a robot but also programmed for seduction.

The central comedic conflict arises from a fundamental contradiction: although Makina was built for pleasure, her artificial intelligence is hampered by strict parental internet controls that prevent her from accessing any information of a sexual nature. This leaves her completely inexperienced and reliant on flawed data, often sourced from a female classmate obsessed with Boys Love manga, leading to hilariously awkward and technically misguided advances on the flustered Eita. Eita, for his part, is a virgin overwhelmed by the situation, struggling to contain his embarrassment while also bearing the immense pressure of keeping Makina's true identity a secret from their classmates and the public.

The story unfolds in a version of modern Japan where highly advanced androids secretly integrate into society, possessing abilities such as transferring their consciousness into digital devices or swapping modular bodies. The situation grows more complicated with the introduction of other androids. Makina's "sister," Mimika Imose, is a pint-sized spy-type android who yearns for a more mature body and plots to swap with Makina. Another sister, Alma Sakimori, is a powerful combat android who is accidentally activated by Makina's best friend, a hardcore fujoshi named Mamimi, leading to further chaotic interventions. As they navigate their peculiar cohabitation, Eita and Makina encounter additional challenges, including suspicious landlords and the potential threat of Makina being "retrieved" by her creators, all while their unusual relationship deepens through a series of risqué misunderstandings and genuine, if awkward, attempts at connection.