Avon takes care of Omar's man Brandon but Wallace, who saw Brandon in the arcade, isn't too comfortable when he sees what they've done to him. Avon gives D'Angelo and Wallace a bonus for their good work. The police meanwhile get authorization to place taps for the pay phones used by D'Angelo and his crew but can only listen in when one of their suspects is using it meaning they'll have to keep the phones under constant observation. McNulty is in a tight spot when Major Rawls gives him a week to report back to his old job. When he realizes the connections McNulty's made in the various shootings, he announces he's going to arrest the Barksdales for murder and threatens to mess up the drug investigation.

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.

While Greggs' life hangs in the balance, the entire department attempts to hunt down Savino. When Wallace flips, willing to testify that Stringer, Wee-Bey and Bird killed Brandon, Daniels stashes him in his grandmother's house on the outskirts of the city, but he soon becomes restless. Stringer tells Wee-Bey he needs to get out of Baltimore until the Savino investigation cools off, while Avon considers his next move. When McNulty and Pearlman try to pressure Levy into giving up Savino, he proves smarter than they gave him credit for. Meanwhile, when the detail's hand is forced, and a series of city-wide raids are ordered so as to appease Burrell's desire for "dope on the table," McNulty goes to see Phelan for help, but is surprised at his reaction. Daniels decides not to raid the main Barksdale stash house, but when word of his plan gets back to Burrell, he realizes there is a snitch in the detail. Elsewhere, Bubbles finds it increasingly difficult to stay clean.

Due to the camera at Orlando's, the detail gather enough information to arrest Avon and many of his people, but, with Wallace dead, they are unable to bring charges against Stringer, who's left on the street. However, disgusted that Avon and Stringer had Wallace killed, D'Angelo flips on the entire organization, giving the detail more information than they could have ever hoped for. As Daniels figures out who the snitch is in the unit, Herc is shocked when he is passed over for promotion in favor of Carver, who scored lower on the sergeant's exam. In Philadelphia, Wee-Bey is arrested and gladly admits to murder after murder. Finally figuring out why Avon has been buying vacant properties in the city, Daniels, McNulty, Freamon and Pearlman take their evidence of political involvement to the FBI. Meanwhile, D'Angelo's mother, Brianna (Michael Hyatt), attempts to convince him to stand with the family.

Bodie's disastrous sales efforts result in a tongue lashing from Stringer Bell. Ziggy pulls Johnny Fifty into a new caper that makes the Greeks pay big money. McNulty goes undercover in a brothel. As Valchek fumes over the change of targets and Burrell pulls the rug from beneath him, Daniels and Pearlman maintain their composure.

After the notorious Franklin Terrace public housing towers are razed, the Barksdale drug crew searches for a new home on the streets of West Baltimore. McNulty and the detail look to make a case against Stringer Bell with a wiretap on a drug ring run by his ally, Proposition Joe. Daniels' promotion is derailed by City Hall due to his estranged wife's political ambitions.

Omar continues his bold strikes on the heavily guarded Barksdale stash houses. McNulty launches his own investigation into last year's prison suicide of D'Angelo Barksdale. On the streets the bloodbath continues, prompting Burrell and Rawls to jack up the heat on their district commanders. The street violence also presents Daniels with a tough decision. A beleaguered Cutty tries to get his life back on track.

The brutality at police headquarters continues over the perceived failure of department commanders to rein in the city's crime stats. Another hit by Omar on the Barksdale stash houses goes horribly wrong. Proposition Joe summons Stringer Bell to a meeting and tells him that the cops have screwed up. Daniels reassigns his detail after the wire on Stringer Bell goes dead.

In the Season Four premiere, four boys from West Baltimore play out their summer vacation in the streets. Meanwhile, Marlo has solved the problem that baffled Stringer Bell: how to maintain discipline--read: murders--without getting police attention.

Herc's soft-duty job with the mayor takes an unexpectedly hard turn. Despite the potential damage to her career, Pearlman provides Freamon and Sydnor with subpoena ammunition for their 'grizzly bear' hunt in City Hall.

The ensuing negative attention turns Royce against Burrell, who takes the heat while Rawls comes to the rescue. At school, Prez's reward/punishment program meets with mixed results, and Colvin looks to restore order by separating disruptive "corner" kids from more attentive "stoop" ones. Chris tries to enlist Michael into Marlo's ranks, spooking Randy along the way. Dukie debunks Randy's "special dead" theory.

With Election Day approaching, the three mayoral candidates make last-minute appeals. Carcetti wrangles for votes as he responds to a potentially devastating smear. Norris and Greggs get a lead on the Braddock case, but end up being detoured.

With a bounty on him, Omar calls in a favor to Bunk. The election over, Royce and Carcetti make peace and contemplate their futures. At school, Prez tricks his students into learning math. Finally, Greggs uses 'soft eyes' at a crime scene.

To monitor the pulse on the street, Carcetti makes the rounds with members of the force. While Proposition Joe shows off his vocal range, Chris shows Snoop how to expose, and dispose of, New York infiltrators. Colvin uses "corner" logic in class. A newly sober McNulty attends an Irish cop wake - with a not-so-sober Bunk. Michael is dismayed by the unexpected return of a missing family member.

After flexing his muscles around the city, Carcetti faces his first dilemma when a group of ministers protests Herc's mistreatment of one of their own. Randy gets the cold shoulder at school. Omar and Reynaldo pay a menacing visit to Proposition Joe, with their own proposition. Freamon has a revelation at a crime scene that promises to blow the lid off an unsolved mystery.

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.

Season Five premiere. As McNulty and the detail continue staking out Marlo's crew, recently promoted Sergeant Carver is welcomed by a cauldron of discontent from officers coping with unpaid overtime.

Campbell tries to smooth out the transitions in the police department. The newspaper scrambles to confirm surprising news from City Hall, but lose out to the TV media in scooping a high-profile Grand Jury appearance.

Mystified by Omar's disappearance, Marlo and Chris ramp up their efforts to locate their nemesis. After a sparsely attended waterfront ceremony, Carcetti fires away at a larger press event--and recasts himself as a champion for the homeless.

An unexpected call puts Templeton back in the spotlight--and gets McNulty more attention than he expected. Bunk bucks at Landsman when ordered to help with the force's most recent red ball.

Baltimore's renewed police commitment brings fresh recruits to Daniels and McNulty, starting with Carver. Facing a new political challenge, Carcetti is forced to make dangerous political deals.

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.