Born to rival families on the same day with the same name, Seok Jiwon and Yun Jiwon grew up fighting whenever they looked at each other. Their fierce rivalry masked a deep love, which faded by the summer they turned 18 years old. 18 years later, at the age of 36, they are jaded and disillusioned with romance. However, they find themselves thrown together again, as the chairman and the gym teacher of the same high school. The bitter enemies must confront their past, sparking a passionate reunion that challenges their perceptions of love and rivalry. Some flashing lights sequences or patterns may affect photosensitive viewers.