The Reagans argue the advantages and disadvantages of profiling; Danny, Frank and the rest of the NYPD search for a homemade bomb about to detonate in the city.

When an unidentified young girl is found murdered at a debutante ball, Danny and Jackie look to the prostitute found giving her a hard time on the hotel's surveillance camera for clues. Meanwhile, Nicky gets a glimpse of her first murder victim as she rides along with Danny when he gets the call to investigate.

Jackie goes undercover as an escort when she and Danny track down a serial killer who is murdering prostitutes in hotel rooms. Meanwhile, Erin meets a potential suitor at an art gallery who shares her interests.

Danny and Jackie investigate the murder of a Reagan family friend who was an undercover detective. Danny's family starts to worry as the persistent search takes an emotional toll on him.