Frank goes on high alert when a threat to New York City may be imminent following a terrorist attack in the Middle East.

Danny and Maria investigate a possible serial killer who sends a chilling message to Danny, and Erin toys with the idea of applying for a judgeship.

When newspaper reporter Lorenzo Colt (Zachary Booth) is targeted while wearing NYPD gear on a ride-along with Jamie and Eddie, Frank puts Danny and Maria on the hunt for the shooter who may be out for other members on the force. Also, Garrett contemplates

Erin's attempt to convict a slippery mob boss for an old murder is muddled when her former informant, Vincent (Dan Hedaya), leaves witness protection to provide his old boss with an alibi. Also, Frank finds himself in a departmental war with Commissioner

Danny joins the hunt for two escaped convicts after hearing one of them is someone he helped to wrongfully imprison. Esai Morales guest stars.

When Jamie is caught on camera committing what could be construed as police brutality at an anti-policy demonstration, Frank is forced to turn the case over to Internal Affairs. Also, Danny and Maria investigate a rape case involving a civil rights attorn

Danny and Maria investigate the theft of the famous car that was driven in a classic film, now owned by Owen Cairo (Anthony Edwards).

When Danny and his family are threatened by Thomas Wilder (Louis Cancelmi), a serial killer Danny has been unable to apprehend, Linda's concern intensifies over her husband's job as well as the state of their marriage.

When a homicide case ends in a hung jury, Erin is forced to take over the case from her colleague, ADA Kelly Blake (Diane Neal), and with the help of DA investigator Anthony Abetemarco (Steve Schirripa), find a missing witness. Also, Jamie and Eddie go un

Danny is interrogated by the District Attorney's investigator when his ex-partner is accused of planting evidence in order to wrap up a homicide case.

When Frank's first partner announces plans to publish a book filled with stories of their early days on the force, Frank worries about his personal stories being made public.

When a local mobster is gunned down in his car, Danny and Maria try to get information from the mob's low-level errand boy they find tied up in the trunk before the gang retaliates.

When a well-regarded, newly retired NYPD lieutenant is accused of shooting a group of potential muggers on the subway and then disappears, Frank must deal with the fallout.

Danny must determine who murdered a man when multiple women who worked for him all take credit for it.

Erin is overwhelmed with guilt after a man she set free is accused of killing a cop.

Linda asks Danny and Baez to help her co-worker who is having trouble with her angry ex-husband. Whoopi Goldberg guest stars.

Jamie and Danny disagree about how to handle a reckless NYPD rookie, Marcus (Michael Drayer), who is the son of Danny's friend.

Frank and Danny work together to help Nick Constantine (Michael Nouri), a rehabilitated ex-con who Frank put away years ago, when Constantine becomes involved in the murder of an old enemy.

While hunting for a robbery crew on a wild crime spree, Danny and Baez partner with Detective Jimmy Mosley (Johnathon Schaech), a detective from another precinct who broke Baez's heart years ago.

When serial killer Thomas Wilder (Louis Cancelmi) attaches a message to his latest victim that taunts Danny, their deadly game of cat and mouse becomes personal for Danny.

When a key eyewitness in a murder trial flees out of fear of retaliation, Erin and Anthony spearhead their own two-person manhunt to find him and convince him to testify.

Frank, the Mayor, Erin and the DA's office contend with public outrage after a grand jury doesn't indict an NYPD officer for the controversial shooting of a teenager that was caught on video.