Sin City is an exploration of Basin City, a dark and miserable place filled with corruption. The movie follows three residents who become entangled in violent and corrupt situations. It deals with themes of revenge, violence, and police corruption. The plot revolves around a police officer trying to protect a young girl from a serial killer, a man seeking revenge for the murder of his lover, and a group of prostitutes defending their territory against the mob. Sin City is a neo-noir crime thriller that delves into the dark underbelly of a fictional city.

In Sin City, Marv wakes up with no memory but traces his steps. Johnny wins big in a poker game and seeks revenge. Dwight tries to rescue his former lover Ava from a dangerous situation. Nancy seeks vengeance on Senator Roark. This graphic, stylized film depicts the intertwined stories of these characters in a city filled with corruption and violence.