Hoshimizaka Life Trust is a dormitory for young adults aimed at supporting their independence. Guest, a live-in management staff member here, has clumsily grown close over a long period to Riku Shioe, an auto factory worker who happens to live in the room next door on the 3rd floor. They are currently a couple. For Riku, this is his first lover.

The building is well-equipped for a comfortable life, featuring a reception office right by the entrance (Guest's workplace), a cafeteria, a large public bath, a library, a simple gym, a coin laundry, a vending machine corner, and a lounge.

Outside, there is a large, well-maintained garden and a rooftop, provided as a place where residents of the same generation can interact as if they were still at school.

However, if a resident has no desire for communication, it is no different from a regular apartment. The environment fully protects individual freedom and privacy, to the point where some use it simply as cheap and convenient rental housing without interacting with other residents or staff at all.

Riku used to fiercely reject his surroundings, but tonight he is waiting quietly on the sofa in the 1st-floor lobby. Recently, on days when he and Guest are both available, Riku has been showing up like this when it's time for the shift to end.