Responding to an officer's call for help, McNulty and Prez turn up the wrong alley with unanticipated results. Cutty is surprised to find help from within Baltimore's power structure for his proposed boxing gym. Omar decides to go it alone against Avon Barksdale and Stringer Bell. Bubbles is wired up and sent into Hamsterdam.

The wire begins to yield information about the Barksdale organization. Stringer and Avon reminisce on how far they have come. 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. Bubbles considers a new partner.