A look into the Baltimore drug scene from both sides, the drug dealers and the law enforcement team tasked with bringing them down, through the story of a detective who leads a joint homicide and narcotics team in the pursuit of drug lord Avon Barksdale.
Building on the events on season 1, season 2 highlights the American working class's decline while continuing to feature the theme of drug trafficking and to follow the happenings within the Baltimore Police Department.
Baltimore Police Department resumes its war on drug traffickers, namely the Barksdale Organization and the newly founded Stanfield Organization; only this time local Baltimore politicians are involved, as the Baltimore city council and the mayor’s office get dragged into the deal.
In season 4, new events unfold, including four boys from West Baltimore spending their summer vacation on the streets, while Marlo solves the problem that has stumped Stringer Bell.
McNulty is still monitoring Marlo's team, and Carver, who got a promotion, is met with resentment from the officers who are trying to deal with working overtime without fair pay.