Having been betrayed in her latest relationship, Ji Soo believes that people's garbage reveals their true colors. One day, she comes across garbage that's been neatly sorted and discarded, which immediately piques her interest. The person who did such a good job is none other than her next-door neighbor, Woo Jae. She grows curious about him and goes as far as collecting clues found in his trash to amass the information to get closer to him. As they get to know each other, Woo Jae's warm-hearted and friendly temperament allows her to open up little by little. Then a chance meeting with his ex-girlfriend, Se Ra, hurts Ji Soo's feelings. Unable to trust Woo Jae again, Ji Soo treats him with cold indifference. Woo Jae becomes troubled by Ji Soo's sudden change of attitude. One night, he sees Ji Soo enter the apartment building with a trash bag in her hand and follows her. They have a fight, and the bag bursts open, exposing Ji Soo's secret. After that day, Ji Soo's apartment seems to remain empty.