For Kwon Seung-ji, life was always like a cart sitting on top of a hill. Just a single light push was enough for her life to gain an unsettling speed, rattling and always heading downward. Watered-down whiskey, a knife wrapped in electrical tape, and fake erectile dysfunction pills that kept crumbling—these were all shoved into the darkest corners of Busan along with Seung-ji. After dipping her hands into the filthy water and enduring today, Seung-ji discovers a new job: smuggling cigarettes. The smuggler she contacts in the outskirts of Busan is a rookie, four years younger than her. "Kwon Seung-ji, how old are you?" "...I'm twenty years old." After deciding to make a big score and leave this place, Seung-ji's age, expression, past, and future all had to become lies from that moment on. At least to the twenty-one-year-old in front of her.