Ron Nakahara

Voight (Jason Beghe) is assigned a new Internal Affairs handler, Stillwell (guest star Ian Bohen) who proves to be suspicious of Voight's actions. During an investigation involving a gambling ring Voight is forced to work with his former partner from the Gang Unit, Shi (guest star Mark Dacascos). At the same time Halsted (Jesse Lee Soffer) remains fixated on Lonnie Rodiger (guest star Matthew Sherbach) and enlists Jin's (Archie Kao) help to gather more information. Meanwhile, Ruzek's (Patrick Flueger) inflated ego leads Olinsky (Elias Koteas) to take him down a peg and offer a great opportunity to Atwater (LaRoyce Hawkins).

When Morland offers to use his influence to have Sherlock and Joan reinstated as consultants to the NYPD, Sherlock's mistrust of his father makes him question his motivation to help. Also, with no work offers coming in, Watson wrangles a gig with the FBI investigating a triple homicide in a top-secret research lab.

A monkey infected with the AlDS virus bites and kills a lab worker after security guard George Peavey's (Kevin Isola) attempt to rescue the primates. When Briscoe (Jerry Orbach) and Green (Jesse L. Martin) investigate they discover Peavey is the pawn for an animal rights contingent.

When a computer sting uncovers the possible mole in the CIA arms smuggling ring, Elizabeth's questioning of the suspect makes her think that a larger, more dangerous force is behind the operation. Also, Henry worries that the doomsday cult is drugging his embedded operative, and Elizabeth and her State Department staff come up with an unorthodox approach to solving black rhino poaching in Namibia. (TV-14 L, V)