A female officer is shot following a stationery store robbery and later dies in hospital. Danny tries to keep Diane safe. A new ADA arrives. Katie decides to move back home.

Teacher David Lewis comes into the squad-room to talk about Cindy Clifton and a support group that he ran that she was a part of. Sipowicz and Clark let him go but send off some of his left behind chewing gum to DNA for testing. Jones goes to court as its the day when Michael is to testify against his father. Ortiz and Ronson go to the scene where tourist Ned Applebaum has been mugged and lost his wife's $35,000 necklace. Ortiz and Ronson eventually find out that Ned met a lady friend on the Internet and he was going to meet her in Little Italy when he was mugged. He was going to loan her the necklace so that she could use it as collateral for a loan for her sick child. The detectives get the PO Box number where Applebaum had sent previous gifts to his lady friend. Ortiz and Ronson go to the apartment of the owner of the PO Box. He is a day trader/con artist who they discover took advantage of Ned Applebaum. They get the necklace back and Ned is forgiven by his wife. Later, Gibson tells Sipowicz and Clark that David Lewis was found DOA in his apartment. They go to the scene and try to determine whether the death was a suicide or not. Sipowicz tries to decide how to proceed with the investigation of Lewis's death; both he and Clark believe that Brockhurst might be involved. Clark gets a call about Dr. Jennifer Devlin and goes to the hospital. The doctor tells her she needs to remain restrained for now, but he is allowed to see her as long as he doesn't loosen her restraints. Sipowicz finds Brockhurst and tells him of his theory that he killed David Lewis. Brockhurst doesn't admit to anything, but tells Sipowicz he is going to be able to sleep tonight now that the case is closed.

Sipowicz investigates a murder involving the victim's current husband and ex-husband; a longtime informant gives Ronson information about an illegal gun shipment, but the suspect's father is being followed by the FBI; Jones gets into a fight with Craig after he's acquitted of murder charges; and Sipowicz is the proud father of a baby boy.