Jieun hears the news that Seungjo—the person she has had a long-standing unrequited crush on since high school—has gotten a girlfriend.Wanting somewhere to pour out her wounded heart, she happens to discover a chat app called Heart-Pounding Planet. There, she meets someone named “Jemulpo Puppy” and ends up having a brief little fling.Then winter break ends, and Jieun returns to school after being away for a while.“W-wait a second. Why is that person here?!”There, she comes face-to-face with the one person she thought she would never see again—“Jemulpo Puppy.”…?“I found you, little pebble.” +