Greggs learns how Marlo takes care of business; Carcetti reveals his political ambitions; McNulty reconnects with Stringer.
Colvin arms himself with intelligence from Daniels' detail; Carcetti wants to fix the witness protection program; Omar struggles with dissension in the ranks.
Stringer Bell gets an education in construction management; Bunk delivers a searing message to Omar; Daniels keeps up the front of marriage to Marla.
Marlo maintains discipline without bringing police attention; the mayoral candidates hit different campaign trails in the final weeks of the race; McNulty turns down a promotion.
Herc discovers a blast from the past; Omar grapples with guilt; Bunk receives a gift-wrapped surprise; McNulty tracks Terri to Washington.