Choi Ko-un, who loves his girlfriend to the extent that it feels like he could perish, and Han Song, who feels slightly bashful about her overly affectionate boyfriend yet appreciates his love, are a joyful couple. Their only concern is a minor one: "What costume should we try tomorrow?" Today, they enjoyed another sweet and passionate moment together. However, Han Song suddenly begins to feel troubled by memories of her ex-boyfriend and the thoughts of those around her. She starts to ponder, "Will Ko-un ever change too...?" and begins to feel a bit anxious.