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.
With his lead dwindling, Royce resorts to extreme measures to stall Carcetti's momentum. At Bodie's corner, Michael proves adept as a runner, with Bodie and Marlo taking notice. A re-up bodega is put under surveillance by Omar and Greggs.
With Freamon and Greggs moved to Homicide, Herc and Dozerman join Marimow in the stripped-down Major Crimes Unit. Cutty gets a 'custodial' job at Tilghman School mopping up truants, but can't make headway in his efforts to mentor Michael.
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.
Poot returns to the corner after a stint in prison--and is welcomed back. Carcetti engages in a testy budget battle with City Council President Campbell, promotes Daniels, and hits a snag in his efforts to relieve Burrell of his duties.
Acting on Clay Davis' advice, Burrell seeks to burnish his reputation by ordering the department to double their street arrests. The mandate does not sit well with McNulty, who sets his sights instead on cracking a string of church robberies.
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.
On the trail of missing bodies, Freamon turns to a higher authority after being rebuked by Landsman. Carcetti finds his promises of prosperity undermined by the school debt, forcing him to contemplate groveling before the Governor in Annapolis.
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.