Yoona and Seohyun are spy agents of NIS, who always get their jobs done. But being agents means, they have to go out of the country all the time. When they finally have six months of break from work, they grab the chance to be with their son, only to realize he doesn't know them. And they too doesn't know him well besides his name.

The Third Installment of Yoonhyun Story and probably the last.    This will be a mix of one-shot stories and short stories.