Eun Dan Oh is a 17-year-old high-school student from a wealthy family who suffers from a lifelong heart condition that inevitably means she will not live past her teenage years. However, when Dan Oh realizes she is experiencing long gaps in her memory as well, she comes into the unhappy inheritance of another fact in her life: she is a character in a Korean webtoon and all of her actions are predetermined by the artist who draws her. To make matters worse, she discovers she is only a supporting character in the cast. With her newfound understanding of the world she inhabits, she is determined to find true love in her own plot-line and circumvent the author's plans for her character by utilizing the flashes of storyboard she alone is able to see.