Brilliant physicist roommates Leonard and Sheldon meet their new neighbor Penny, who begins showing them that as much as they know about science, they know little about actual living.
Nancy's past keeps getting more interesting. The Bens continue to investigate Squeakie's murder and the heist. Bishop gets targeted to try and get to Knox. Carlene becomes more interesting and powerful.
Magnum and Higgins disagree about being hired by a woman who wants them to recover her $3 million in stolen drug money in order to save her husband's life.
Henry and Danny butt heads over a case involving a man who is volatile toward his wife; Frank is caught in the middle of an ongoing battle between the NYPD and the FDNY