Burrell reluctantly sides with Daniels in the disagreement with Rawls, giving the detail more time to make a case against Avon, despite his fears the operation is beginning to sprawl. McNulty and Pearlman present the detail's findings to Phelan, who signs an affidavit for a further thirty days of electronic surveillance. Using information from the wire on the pit pay-phones, the detail catch a runner on his way to the pit with a re-up. However, they elect not to arrest the driver, Anton 'Stinkum' Artis (Brandon Price), so as to avoid giving up their evidence in the charging documents. Stinkum's apparent free pass from the police convinces Avon and Stringer that their operation has been compromised, and Stringer introduces a new set of operating procedures. Rawls gives Det. Michael Santangelo (Michael Salconi) a choice; acquire information that he can use against McNulty or solve some of the department's open homicides, whilst the owner of Avon's strip club, Wendell 'Orlando' Blocker (Clayton LeBouef), has a proposal for D'Angelo. Meanwhile, Bubbles and Johnny attend an NA meeting, and Bubbles is moved by a speech given by recovering addict Walon (Steve Earle). Investigating the murder of the witness in D'Angelo's trial, with some help from Omar, the detail target Barksdale hitman Marquis 'Bird' Hilton (Fredro Starr).

D'Angelo speaks to Wallace, who tells him he wants to go back to school and get out of the Game. However, Malik 'Poot' Carr (Tray Chaney) discovers Wallace has started using cocaine to help him deal with his guilt over Brandon's murder. Freamon gets Sydnor and Prez started on the complex Barksdale money trail, including possible political connections, and they are surprised to find Avon's corporations have been buying up vacant buildings in run-down parts of the city. Greggs and Freamon approach D'Angelo's girlfriend, Shardene Ennis (Wendy Grantham), who works at Orlando's, in the hopes they can turn her into a CI. After Bubbles narrowly avoids a beating whilst stealing a package that turns out to be stepped on, he decides to try to get clean. Avon and Eastside kingpin 'Proposition' Joe Stewart (Robert F. Chew) stage the annual East vs. West basketball game, but when the detail follows Avon afterwards, they get something they never expected. Meanwhile, having already killed Stinkum, Omar sets in motion a plan to gain revenge on Avon for Brandon's death.

Avon, Stringer and Wee-Bey discuss how best to deal with Omar after the attempted hit on Avon, deciding to let him think they want peace, whilst secretly planning to kill him. As such, Omar and Stringer meet for a parley, with security provided by Prop Joe. Meanwhile, Stringer insists on decreasing Avon's visibility in light of the detail's attempt to follow him after the basketball game. An irritable Phelan signs an affidavit for the new phone being used by the pit crew, and Pearlman tells McNulty that he is not up for automatic re-election, possibly because of the feathers he has ruffled due to his involvement with the Barksdale case. D'Angelo tries to understand why Shardene has left him, and after being clean for three days, Bubbles gets some advice from Waylon, before turning to Greggs for support. Meanwhile, McNulty attempts to flip Wallace, and the detail identifies Barksdale's main stash house. However, when Orlando's attempt to purchase weight gets him a lot more than he bargained for, Burrell sees an opportunity for a dangerous undercover operation.

In the Season Four finale, the bodies from the vacants pile up while Burrell offers his support to Daniels and admonishes Rawls for crossing him. A distraught Bubbles finds himself at his wit's end after his revenge plan backfires.

Although he tells Sydnor the Davis investigation could be a 'career case,' Freamon keeps a wary eye out for Marlo, who takes care of some unfinished business and strikes a business deal with Barksdale.

Marlo forges an alliance with a drug connect, who shows him a new communications trick. McNulty's case gets increased attention from the newspaper, in large part thanks to the addition of Templeton to the reporting team.

With Steintorf ordering Rawls to initiate 'creative' remedies for the rising crime rate, Freamon's vigilance pays off with a promising lead, sending Sydnor and the department into overdrive.

Carcetti maps out a damage-control scenario with the police brass in the wake of a startling revelation from Pearlman and Daniels. Their choice: clean up the mess...or hide the dirt.