When a series of drive-by murders occur after six wrongly convicted men are released from prison, Danny and Baez wonder if they were orchestrated by these men as an act of revenge. Jamie and Eddie find themselves in a life-threatening situation.

It's all hands on deck for the Reagan family, as they race to stop deadly mayhem in the city when the gangs of New York unite to demand amnesty and the release of their imprisoned members and those awaiting trial.

After getting a match from an unknown relative from a DNA network, Sean Reagan does some detective work to figure out who this mystery person might be. Frank gets a personal request from a woman to transfer her son to a safer assignment. Danny seeks to uncover the truth behind the murder of a key witness in one of Erin's cases. Eddie begins to think about having a child after she and Jamie discover a newborn left outside their precinct.

One of the Reagans is shot by a gang member, and Danny pursues a suspect while trying to keep his emotions in check. To add to the complications, Danny has to find an inventive way to bring in witnesses.

In his attempt to expose the Blue Templar, Frank chooses to bypass Internal Affairs after a drug bust indicates dirty cops are involved.

As the Reagans rally together to take down the leader of the gang responsible for the murder of someone close to them, Danny looks to the gang leader’s girlfriend to lead them to him. Meanwhile, Frank is left reeling from a second loss.

As Jamie and Eddie's wedding day approaches, Frank worries about the toast he'll deliver at their rehearsal dinner. Erin interviews a witness whose story leads her to doubt Eddie's honesty. Danny and Baez unravel the complicated love life of a young homicide victim.

Shockwaves ripple through the Reagan family when Danny discovers that their newest family member Joe is working undercover for the ATF to bring down a gun-running organization.

The Reagans band together to prevent Joe from being killed in the line of duty like his father when they fear that his cover has been blown within the gun-running outfit he’s helping the ATF bring down.

Danny blames himself when a young woman commits suicide because he had made a promise to her in the wake of her parents' deaths. Meanwhile, violence involving a gang at a housing project erupts and affects the Reagans.

Danny becomes the lead hostage negotiator when an informant in a large drug case holds Erin at gunpoint inside the courtroom.

Baez gets injured while escorting confiscated drugs, so Danny goes after the drug cartel responsible. A lieutenant with a commendable record engages in controversial behavior, putting Frank in a difficult situation.

Jamie stands up for an officer who is harassed for testifying against her partner. Erin learns her lover may be her boss at the DA's office. Danny asks Erin to file murder charges against a man who shot a 15-year-old girl who ended up dying 8 years later.

Frank is put in a difficult position when Danny is charged with using excessive force. Jamie meets a female doctor, and it makes Eddie uneasy.

A woman's abusive boyfriend targets Jamie after he intercedes in a domestic dispute. The press gets hold of an illegal tape capturing Henry's insensitive comments, and Frank must deal with the ensuing scandal.

After an EMT is shot and killed, Danny and Baez work to determine who is behind a chain of ambulance robberies. Frank defends New York's homeless after the mayor puts a new law in place. Eddie offers to help Jamie pay off his student loans.

Danny’s car matches an NYPD description of a car involved in a drug deal and he is taken into custody when a bag of cocaine is found in his trunk.

Danny uncovers shocking information while investigating a case against orders.

When NYPD Deputy Chief Donald Kent and his wife are gunned down in an apparent gang hit, Frank orders the entire department to scour the city for his friend's killer.

When the son of Frank's most outspoken critic is murdered, Frank and the boy's father must put aside their differences to seek justice.

When Danny intercepts a shipment of several million dollars that was heading to a drug cartel in Mexico, he becomes a target when they come back for revenge. Jamie works independently to track down a serial killer who preys on the elderly.

After someone breaks into Luis Delgado’s home and kills his wife, Luis and Danny team up to take down the vicious murderer who may also be responsible for Linda’s death. Frank finally meets Eddie’s mother. Jamie and Erin are at odds after Jamie seeks her help charging a man who confessed to him while under the influence.

Frank is taken by surprise during an on-air interview with Erin's boss. Danny and his new boss clash as they investigate a drive-by shooting. Jamie and Eddie help out detectives with an apparent suicide.

When Danny and his family are threatened by a serial killer Danny has not been able to apprehend, Linda’s concern intensifies over her husband’s job as well as the state of their marriage. Jamie challenges his superior officer during a hostage situation.

Danny and Baez race to find a missing girl who will die within 72 hours without her heart medication. Jamie and Eddie are on the wrong side of an investigation after engaging in a car chase. Frank, Garrett and Gormley investigate the rise in the settlement of lawsuits against cops. Sean wins an essay contest and receives a medal from former New York City Mayor David Dinkins.