Casey Shraeger and her new partner, James Walsh, try to catch a family of criminals that has the entire 2nd Unit running all over New York until Walsh and Shraeger discover their motive. Meanwhile, Sgt. Brown has Shraeger investigate Walsh's past when it becomes known that her former partner turned out to be a dirty cop. Also, Henry Cole's former partner-in-crime returns, making it even more difficult for Cole to continue to hide his criminal past from the rest of the detectives.