Yui

Yui is the married aunt of Yuu, but since her husband works too, she sometimes comes to Yuu's house and spend to night there because her workplaces is nearby. One day she has come to vist him and play videogames during her vacation in order to relax, but when Yuu's firned Ryouichi has come to play with him, she decided that she prefers to "play" with him.