In the conclusion of a two-part story, a serial sniper is still at large -- and now there's a copycat killer on the loose. While the city is in full panic mode, the men and women of the homicide department work 24-hour shifts to track down the killers. Elsewhere, Howard (Melissa Leo) recovers from her wounds; Pembleton (Andre Braugher) agonizes over the well-being of his pregnant wife; and Giardello (Yaphet Kotto) coerces the newly demoted Russert (Isabella Hoffman) to come out of her self-imposed exile. ~ Hal Erickson, Rovi