As Carcetti prepares to begin his term as mayor, he finds the going tough as he encounters unexpected opposition from the city council president, who is upset that Carcetti and Gray both jumped ahead of her in line to campaign for the Mayor's seat, which Royce had promised to her. Carcetti tries to find away to dump Burrell as police commissioner, but finds that he can't fire him for fear of backlash from the black community, and the cagy Burrell refuses to resign- so Carcetti makes Rawls the de facto leader, reducing Burrell to a puppet. He also promotes Daniels to colonel, keeping him in line for eventually taking over Burrell's job, and promotes Valchek to repay favors.
Prez and the rest of the teachers are instructed to teach the upcoming achievement test, but Prez is unhappy with the idea and rejects it after trying it once and boring his class.
The ever-enterprising Randy finds a way to put his newfound knowledge of the probability laws of math to work in a dice game and makes enough money to buy his candy wholesale on the internet- once securing help from Prez, who uses his credit card on Randy's behalf.
Michael's troubles with Bug's father continue, so he goes to Marlo for help.
Herc continues to search fruitlessly for Little Kevin until getting a tip from Bubbles, who trades the information for a promise from Herc that he will arrest the man who is shaking Bubs down every day. Herc promises, but leaves the hapless Bubbles in a lurch when Bubs calls Herc for help while he is in the middle of the ultimately fruitless interrogation of Kevin.
Kima, flush with cash from her overtime hours, pays a surprise visit to her ex-girlfriend Cheryl to give her some money. She is hearbroken to discover that Cheryl is living with someone else.
Colvin's pilot group sinks its teeth into a competitive group project in which the winning group gets a fancy dinner, but he is dismayed when the winning group members revert to old behaviors after finding the fancy restaurant overwhelming to their inner-city sensibilities.
Proposition Joe continues to feed police information to Marlo, advising him to dump his phones, since Herc, who has been hassling Marlo, is associated with the Major Crimes unit, which is known for wiretaps.
Joe later gives Marlo the location of Andre, who Marlo has found out gave the police information about the robbery/murder Marlo had tried to frame Omar for (Andre had earlier sought Joe out for assistance in going on the lam).
This sets up a truly wrenching scene in which Andre begs Snoop and Chris, Marlo's assassins, not to dump his body in a vacant house, leaving it at the mercy of the rats.