Kang Gary and Song Jihyo are just acting to be couples in a variety show called, Running Man.  In those years since they started to shoot together, Gary takes care of Jihyo like his own little sister but then he realize that she's more than that.  So then there is one day where all gary's cheesiness and cute fight occur. What will Jihyo do and what is her response towards Gary who acts like a little child to express his true feelings? What will their ending be?  Catch