Original title: メス堕ち！魅惑の人妻ライフ ～年上妻たちとのいちゃらぶ汁だく性活～
The protagonist is currently staying with older brother's family in order to commute to prep school. But his brother suddenly decides to accept a new job position that forces him to move away, leaving his wife and the protagonist alone at home.
Moreover, surrounding the protagonist are his other sister-in-law, his aunt and a neighbor wife. Thus, his life full of attractive older women begins.