The expressionless older childhood friend won't let go of me the moment I enter her room, showering me with affection

After university lectures end, I enter the room of my childhood friend, Mifuyu Yaegashi, using the spare key. Outside, she's a cool honor student who keeps everyone at a distance, but in her loungewear she clings to me defenselessly, pouring out unconditional affection in her flat, emotionless voice. A daily life of just the two of us, wrapped in quiet overprotectiveness.