Yuzuka, a shut-in girl, had only one friend, "Mr. Alibaba." Although they only knew each other through social media, not knowing each other's faces or names, Yuzuka felt that he was an irreplaceable presence whom she could trust. However, one day, she suddenly received the news that Mr. Alibaba had passed away. The death of her friend prompted the girl to take a step forward. What would be the outcome that awaits her?