"I just need you to pretend to be my girlfriend for one time...!!" My wife and I are stunned by my best friend Yu's sudden request. While I'm hesitant, my wife Rio, who's been feeling unfulfilled in our lackluster days, seems surprisingly eager to help. I reluctantly agree to lend her out just once for my friend's sake, but I can't shake off the growing resentment as I see her preparing with a strange sense of enjoyment. I thought she'd be back that night, but apparently, she's staying over at Yu's mother's place after being well-received. There's no way something like this could go wrong, right...?