These three friends are inseparable. Mi-so (Kim Da-mi) and Ha-eun (Jeon So-nee) meet in elementary school and quickly become best friends. In high school, Ha-eun meets Jin-woo (Byeon Woo-seok) and starts to have feelings for him, but he starts to have feelings for Mi-so. When they all meet again as adults, they are very different people, but they try to remember what friendship is really about.