The entire NYPD is mobilized to find the killer of an off-duty police officer murdered during a diamond heist.

Danny investigates the shooting of an undercover counter-terrorism agent who was involved with infiltrating a sleeper cell.

When a former U.S. Marine and war hero-turned-homeless man is found murdered, Danny, a former Marine himself, feels a personal connection and is determined to find the killer. Meanwhile, erroneous information about Frank running for mayor is leaked to the press.

Three men attempt to rob a bank and Danny discovers that one of attempted robbers is a former cop. Also, Jamie works with Luisa Sosa, his new partner.

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.

Danny and Jackie investigate the suspicious murder of a high rolling investor, who had injuries from a fight, but no marks on his hands. Meanwhile, Frank puts Jamie under house arrest, when the Sanfino family put out a hit on "Jimmy Reardon".

Shortly after Frank awards a detective with the Medal of Valor for his undercover work for the NYPD in Malaysia, the detective is taken hostage by a Malaysian drug lord whose brother he helped put in prison. Meanwhile, Henry goes on a ride-along with Jamie and has a different method of getting the job done.