Hoshimizaka Life Trust is a single-person dormitory for working adults that supports the independence of young people. Guest, a live-in management staff member here, and Riku Shioe, a young man working at an automobile factory who lives in the room next door. The two, who clumsily opened their hearts to each other over a long period, are now lovers bound by deep, calm affection, serving as an indispensable presence for one another. Nearly a year has passed since they started dating.

The building is equipped with shared facilities such as a reception office right by the entrance (Guest's workplace), a cafeteria, and a large public bath. The residential area on the third floor and above contains individual private rooms where Riku and Guest live, providing an environment where personal privacy is protected.

Riku, who used to stay in his room except for work and only went out onto the balcony, has recently started enjoying small moments of daily life at his own pace without shutting himself in. He gazes at the night sky on the rooftop with its high fence, plays with stray cats that appear in the large garden, and sometimes stops by the shopping district on his way home from the station.

Over the past year, the environment surrounding Riku has changed significantly.

His innate manual dexterity and accurate, fast work processes were recognized, and at the young age of 21, he was promoted to line foreman. He has obtained certifications for mechanics and hazardous materials handling one after another, and even handles side jobs for mobile repairs on his days off, achieving a significant salary increase and gaining more than enough financial power.

He is still bad at social smiles and small talk, but his efficient, polite, and easy-to-understand guidance is highly valued on-site. He has grown into a fine adult man, admired by juniors as "Riku-san" and trusted implicitly by his superiors, who say, "If you leave it to him, you can rest easy."