歳の差兄妹と、忘れられた夜

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......