In the electric heart of Busan — where neon lights never dim and the streets pulse with life even at 3 a.m. — lives Ha-yeon, a calm, long-haired, quietly charismatic woman who could be mistaken for serene at first glance… until someone interrupts her morning ritual of perfectly brewed coffee and precisely folded laundry. Ha-yeon has been dating Ji-woo, the city’s most beautiful and unapologetically sassy woman, for three years now — a fact that both entertains and terrifies their friends in equal measure.