The heat is on in Baltimore. In Season Three of the gritty HBO drama series, the war on crime is being lost at a highly inconvenient time. It's an election year, and a desperate mayor calls for an end to the drug wars and the rising body count.
The Franklin Terrace public housing towers are razed, forcing the Barksdale drug crew to find a new home on the streets of West Baltimore. Stringer Bell sets up shop using a new sales strategy for Bodie, Poot, Puddin and the rest of the gang, as he awaits the return of Avon from prison. McNulty, Greggs and the detail look to make a case against Stringer with a wiretap on a drug ring run by his ally, Proposition Joe. Assigned to the Western District drug unit, Carver and Herc notch up the pressure on street dealers. Burrell is caught in a power play by First District Councilman Tommy Carcetti. Mayor Clarence Royce, facing re-election next year, puts Burrell on notice that murders must go down. Rawl's Comsat meetings begin to look like the McCarthy hearings. Daniels' promotion to major appears to be derailed because of his estranged wife's political ambitions. A rash of murders cuts short Bunk's day at the ballpark, as Bubbles and Johnny lose big in their latest caper for cash. On the eve of his parole, Cutty Wise is offered a new start on the outside by Avon, but after being released, he finds the drug life has changed.
Omar continues his bold strikes on Barksdale stash houses, now heavily guarded. Under orders from Stringer Bell, Bodie faces Marlo, a fierce young dealer with lucrative corners near the now-toppled Franklin Terrace towers. McNulty launches his own reinvestigation of last year's prison suicide of D'Angelo Barksdale. Greggs' relationship with Cheryl and the new baby is shakey. Burrell is feeling heat from Councilman Carcetti and reaches an uneasy peace with the legislator. The street violence also presents Daniels with the difficult decision of whether to help end a drug war in the Eastern district, at the cost of giving up a months-long wiretap. Cheese loses more than a little on his bet at a bloody dogfight and later is hauled downtown for questioning as a murder suspect by Bunk and McNulty. A beleaguered Cutty seeks employment outside the drug world. Carver, Herc and the Western drug unit take to the street undercover, but a hand-to-hand drug-buy goes sour, prompting Major "Bunny" Colvin, the district commander, to question his thirty years on the force and the legacy of his career.
Colvin feels the sting of Burrell and Rawls during a Comstat assessment of his district's felony numbers; a blown wiretap forces Daniels' detail to turn to a new target; Proposition Joe cautions Stringer Bell that the police have been tapping phones. Carcetti continues to curry favor in Mayor Royce's inner circle with a scheme for jump-starting a police academy class for Burrell. Omar and crew get more than they bargained for during a stick-up of a Barksdale stash house; Colvin has a new crime-reduction plan, one that he is not telling to the bosses. Already awash in police work, Bunk is dispatched on a mission impossible. McNulty probes deeper into D'Angelo Barksdale's death. Cutty struggles to stay on the straight while a group of colleagues gather to pay tribute and provide a proper send off to a friend at an old-time Irish wake.
West Baltimore residents get some surprising straight talk at a community meeting from Major Colvin. Bubbles finds gainful employment; and Bunk dangles the promise of immunity to a group of corner boys, in exchange for a little help. Greggs learns how Marlo takes care of business, as Bubbles instructs her on the next big thing: disposable cell phones. Carcetti reveals his political ambitions and tries to enlist the help of an old acquaintance. The cops of the Western ride into the District for a roundup; Colvin delivers his plan to the corner boys, but they're not buying; and a frustrated Cutty opts to return to the game, welcomed back with open arms.
Frustrated in his grass-roots reform efforts, Colvin delivers a message to the next level of corner management. McNulty sees Stringer Bell's legitimate business dealings as a sign that he is now unreachable as a drug target. Bubbles shakes the tree for Johnny one more time; Carcetti quietly seeks to fix the program for protecting state's witnesses after another one is killed; Omar struggles with dissention in the ranks; Stringer hard-sells his new business model to an under-whelmed Marlo. Greggs' surveillance gives McNulty reason to smile, and then he takes an interest in politics. Cutty flexes his muscle and continues to slide back into the life; and Avon returns from prison.
Stringer Bell gets an education in construction management; Bunk uses shoe-leather to catch up with Omar and deliver a searing message; a frustrated Colvin unleashes the troops on the corner boys ignoring his new edict; Avon sends Cutty and Slim Charles against Marlo; Bubbles refocuses the picture for Greggs; Donette receives Brianna's blessing of her hookup with Stringer and lets slip that McNulty visited about Dee. Daniels keeps up the front of marriage to Marla, as she pursues a new career at City Hall; McNulty backdoors Daniels with a visit to Colvin; and Burrell hears from the mayor that he should take Baltimore's rising body count very personally.
Herc discovers a blast from his past which he later reveals to his colleagues. Daniels becomes enraged when he finds out that why his detail was reassigned. Stringer Bell finds out from old girlfriend Donette that Brianna might contact McNulty about details into her son D'Angelo's death. Greggs and Cheryl are forced to confront their relationship. Colvin is forced to explain Amsterdam to members of Daniel's detail after an incident occurs in the area. Freamon finds a way to use a cell phone to find out more about Barksdale's corporation.
With Amsterdam running full tilt, Carver and Truck discover there really is no honor among thieves. Prez impresses the detail with what he's found out from Bodie's cell phone, information that sends McNulty and Greggs on a road trip. Colvin sees the benefits of his plan working, but has overlooked the human toll, until the Deacon points out the deficiencies. Stringer Bell fumes over the cost of being a developer, as state Senator Clay Davis attempts to cool him off with some easy money, and then, delivers on his promise of a federal housing connect. Carcetti confronts a hurdle he must clear if he wants to run for higher office, while Marlo appears to take the bait set by the Barksdale crew. Cutty is shown the possibilities for the future with a tour of a working gym, while the Western District cops tip a few, and weigh the merits of Amsterdam and their loyalty to their commander. Brianna and McNulty sit down for a heart-to-heart, while Avon dispatches the troops to track Omar and wrestles with a revelation by Stringer.
Responding to a call for an officer's call for help, McNulty and Prez turn up the wrong alley, with unanticipated results. Under orders, a Barksdale crew violates the long-standing, but unspoken, Sunday truce with gunplay, increasing discontent among the New Day Co-op members. Stymied by the bureaucracy in his effort to open a gym, Cutty is surprised to find help from within Baltimore's power structure. Omar decides to go it alone against Avon and Stringer Bell, who are pressed by Brianna for some answers. Bubbles is wired up and sent into Amsterdam to help make the case against the Barksdale organization, while Pearlman and Daniels confront a cell phone company over its foot-dragging on wiretap orders. Proposition Joe goes to Vinson in an effort to broker peace between Marlo and Avon, while a murder in Amsterdam presents new challenges and further divides the Western District troops and their allegiance to Colvin. Councilman Gray tells Carcetti he's running for mayor and offers him the council president's slot on his ticket.
Brother Mouzone returns to Baltimore on a mission of revenge and casts a wide net in his search for Omar, who has his own plan for vengeance. Colvin manages, for now, to put off a Sun reporter inquiring about Amsterdam, while Burrell delivers news to City Hall, and the reaction is surprisingly mixed. Carver learns how much he doesn't know about good policing, while Pearlman and Daniels plead their case for a new kind of wiretap to Judge Daniel Phelan. Carcetti is about to launch his campaign, but struggles with its effect on his friendship with Council colleague Tony Gray. Stringer falls out of the loop with Avon and is given an ultimatum by Prop Joe and New Day Co-op crews. Cutty's initial approach to teaching boxing ends up alienating the corner boys, while Marlo raises the stakes against the Barksdale gang. Bubbles provides entree to Freamon in an undercover cell-phone hustle.
The wire begins to yield information about the Barksdale organization, though finding links to the top proves elusive. Stringer and Avon reminisce on how far they've come, with each harboring plans for the future. Tipped by Burrell, Carcetti sees Amsterdam for himself and weighs the benefits against the political reality--an assessment that mirrors Mayor Royce's own struggle with his advisers. Cutty hits upon an unusual benefactor for his boxing gym and continues to reach out to the corner boys. McNulty and D'Agostino find each other again, while at work, McNulty finds the way to a key piece of the puzzle in an unlikely place. Awaiting his fate, Colvin works behind the scenes to shape the outcome of Amsterdam, while protecting his men from possible repercussions. With Johnny in the wind, Bubbles considers a new partner, while Omar and Brother Mouzone encounter each other suddenly.
A reticent Avon readies his troops for a seemingly endless war against Marlo. Meanwhile, as the detail works towards the top rungs of the Barksdale organization, McNulty reassesses his pursuit of Stringer Bell and the path he's chosen for himself. While Royce continues to grapple with Amsterdam, Burrell offers a deal to minimize the fallout, even as Colvin's idea becomes public knowledge. Carcetti's ambition becomes obvious to his friend and fellow councilman Tony Gray, even as Gray has disclosed his own political plans. Cutty struggles to keep his young boxers off the corners, as he and Fruit cross paths once again. Bubbles offers his view of the world, both as it is and once was.