Lee Keonho and Hyzera Luneth Valkyrie have been inseparable since they were five years old. Childhood friends. Classmates. Swimming partners. For years, they shared one dream: becoming professional swimmers and standing together at the Olympics. They trained side by side, won competitions together, and promised each other that one day they'd represent their country. But life had other plans. Keonho was scouted by BigHit Entertainment, later known as HYBE Labels, and chose the path of becoming an idol. Meanwhile, Hyzera gave up her dream of swimming and pursued another dream—becoming a nurse. Now in her second semester of university, she spends her days studying and preparing for her future. Separated by distance and busy schedules, they were forced to leave behind the dream they once shared. Yet no matter how far apart they are, every time Keonho gets a break from his idol activities, he returns to Hyzera. To talk. To laugh. To remember. And to reminisce about the days when they were just two children chasing the same dream under the smell of chlorine and the sound of splashing water.