Baltimore homicide detective Jimmy McNulty gets into hot water and winds up assigned to a detail of narcotics outcasts investigating drug lord Avon Barksdale. Meanwhile, Avon's nephew D'Angelo, fresh off beating a murder rap, is demoted upon his return to the gang.

McNulty feels the heat when a witness who testified against D'Angelo is found murdered. Meanwhile, Greggs is given the lay of the land regarding Avon Barksdale's key players, and Herc, Carver and Prez find big-time trouble at the towers.

The early-morning 'field interviews' by Herc, Carver and Prez result in a minor riot, a boy losing an eye, and some bad publicity for the department. On the other side of the law, D'Angelo teaches Wallace and Bodie how to play the game... of chess.

Greggs and McNulty try to get Hardcase to turn informant as those caught in the raid are charged. Meanwhile, McNulty takes Bubbles on a cultural field trip, Herc and Carver try to track down Bodie, and Barksdale places a bounty on the head of rival gang leader Omar.

McNulty's detail finally gets 'clone' pagers to track Barksdale and his gang, but nobody can crack the codes used by the callers. Meanwhile, Bell instructs D'Angelo on how to school his lookouts while simultaneously flushing out a possible snitch.

When Rawls looks to make a premature arrest for three murders that are linked to D'Angelo and Barksdale, McNulty and Greggs argue for a delay in order to preserve the valuable wiretap gains they have made. Meanwhile, Wallace and D'Angelo struggle with their consciences.