One day, Hajime Tamachi, an apathetic man, receives an unexpected message from Renafalt, a friend he met five years ago in an online game, whose face he has never seen: “Senpai, how about hiring a home security guard?”Convinced that Renafalt is 200% a man, Tama arrives at the meeting spot and sees someone with a red suitcase, just as they had arranged. However, that person turns out to be a beautiful girl with large breasts.«Ah… A-Are you… Senpai?»Thus begins the peculiar cohabitation of an apathetic man who only wants to live quietly in a corner of the world and a high school girl with social anxiety. The story of their strange life together has begun!