Seo Hyerin is an ordinary schoolgirl with a love for cute things. As she happens to develop a crush on one of her older seniors at school, she decides confessing her feels towards him may be the best thing to do.
But she soon has to notice that things will get complicated as she arrives home, and finds a young man in her home, looking like her current crush. What she then has to hear gives her a shock. Because the young man happens to be her crush and her new step sibling...