Carter, her team (including Fusco) and the organized crime unit are investigating what they know is an execution murder of a mob leader named Benny D'Agostino in a bodega in the Russian mob ruled area of Brighton Beach. The murder was the retaliation hit by the Russian mob on a rival mob infiltrating Brighton Beach, that rival mob led by an unknown man named Elias. D'Agostino was one of Elias' underlings. On the surveillance recording, Carter notices that there was a witness in the bodega who vanished after the shooting. Reese, who gets a call from Fusco about Reese possibly helping to identify and find this missing witness, is one step ahead of Fusco in that he knows that his and Finch's latest case is that witness, a dedicated local schoolteacher named Charlie Burton. As Reese approaches Burton, he knows that the Russian mob are after Burton for being a witness. Reese convinces Burton to go on the run with him to try and get out of the neighborhood. While the Russian mob are in their pursuit, Reese and Burton, who lose contact with Finch, are on their own as they try to get out of the neighborhood to safety in Fusco's custody. As Reese and Burton hole up in no man's land - a building run by the Bulgarian mob - in their effort to find a safe route out, Finch learns that there are people working inside the police assisting one of the mob units. Finch and Reese ultimately discover to where that police infiltration leads, but at that time it may be too late.