Why don't you smile when you're with me these days?". Three years as a senior and junior, four years in a relationship. Seo Ha-ru and Nam Jiseo have been together for 7 years, but Jiseo impulsively suggests breaking up after realizing that Ha-ru's feelings have grown cold. Ha-ru readily accepts the breakup, and shows Jiseo a presentation about why they have to live together for the time being. Jiseo, who falls for it without thinking, reminisces about his memories with Ha-ru throughout their time together.