Toshinosa Kyoudai to, Wasurerareta Yoru

In the near future, virtual reality (VR) has become widespread. - The protagonist is an ordinary office worker who enjoys adventures in one of those fantasy worlds. - He works at his company during the day and spends his evenings adventuring in the fantasy world. - He has a younger sister who is a student, and a pro gamer, they used to get play together and party when she was young. - Recently, however, she became difficult to get along with...... - One day, as Christmas approaches, he notices a light leaking from his sister's room. - She is in the middle of the Christmas event in the game and has been logging in for a long time lately. - The protagonist tries to warn her to go to bed early, but - He gets excited by the sight of his little sister wearing a VR headset and looking so defenceless. - The protagonist, who loves his little sister, is so turned on by her that he ends up masturbating using her defenceless body as fuel......​