O Seong Mu, the father of cardiothoracic surgeon O Yeon Ju, mysteriously goes missing while writing the last chapter of his webtoon "W". Yeon Ju goes to his office looking, but a hand from his monitor suddenly pulls her in, and she finds herself on the rooftop of a building, next to a bloodied man. She manages to save the person, only to realize that he is Kang Cheol, the main character