Frank mobilizes the entire NYPD to find the killer of a police officer who was murdered after a diamond heist.

Danny tries to juggle investigating a case with trying to have a romantic weekend with Linda. Meanwhile, Jamie goes deep undercover into a crime family.

Frank deals with a political crisis after Jamie and Renzulli enter a religious center in response to a 911 call and are injured by the church's security team who prohibits them from entering.

A girl falls from her apartment window and dies. Danny investigates. Henry has a heart attack and spends Thanksgiving in the hospital. Tony gets cash to square off his gambling debt, with a warning from the Commissioner.

A reverend, the mayor and the police organize a gun buyback plan, with no questions asked. There, a gun used in a shooting at a chemist's is traded in. Danny investigates without being able to use the evidence from the buyback program.

A man dies in the reception area of a hospital. The investigation leads to an illegal fight club with heavy betting. The fight was doctored by cementing the gloves of one fighter. Jamie's cover is blown, and he saves Noble from a mob hit.

The police come to know of a citywide biological threat and Frank deals with it. Danny, hunting for a petty thief, gets a tip which helps resolve one of his unsolved cases. Jamie and Danny argue about booking rights for this petty thief.

When an injured woman recants her claim of domestic violence, Danny and Jackie look into it further only to find that the woman is involved in a secret relationship with a high powered councilman who also happens to be a friend of Frank.

Danny and Jackie set out to investigate the murder of a bride on her wedding day in a drive-by gang shooting. However, they are pulled off the case and assigned to the protection detail of a Central American president who they believe is a target for assassination.

Danny is called to the scene on Halloween night, when a man in a priest costume is attacked by a figure dressed as a skeleton. Detective Kate Lansing is assigned to help on the case and she recognizes the skeleton costume as the garb of Baron Samedi, a Haitian spirit of death.

When a man with multiple rat bites is thrown from a moving car, Danny works the case to find out why and who was trying to send a message. Mary Elizabeth Mastrantonio and Mark Moses guest star.

Danny and Jamie are playing basketball with some other guys. A guy Danny knows gets into it with a guy Jamie knows; the guy Danhy knows smacks the guy Jamie knows. The one who was smacked has to be hospitalized and he demands that the one who smacked him be arrested and Danny reluctantly does it. He tells the guy he knows that his sister is the D.A. and maybe he can talk to her. Erin is approached by a man who asks her to re investigate his daughter's unsolved murder which is 15 years old. Erin goes to Danny and asks him to look into the man's daughter's murder. It seems the man thinks that his daughter's boyfriend who's the son of a wealthy man should be considered. Danny agrees, if she helps his friend. Danny goes to see the detective who investigated the murder and he tells Danny that he had an alibi and took a polygraph and passed. Erin informs Danny that his friend has a previous record which means he has to be indicted. Jamie offers to talk to the guy he knows. Erin and Danny see the man and tell them what they learned. He tells them that the guy's father's company has polygraph which he could have learned how to beat it. And he also tells them that his alibi witness was a friend. So Danny decides to look deeper. Frank and Garrett have a disagreement when Frank is interviewed and a very touchy question is asked.

When a man is shot in Times Square, Danny investigates and learns the man had no enemies or reason for someone to kill him. Another person is killed and there appears to be no connection between the two victims. He later learns that the second victim got away with murder so he thinks someone is trying to get payback. Erin takes him to the D.A. who prosecuted the second victim. The man's irate about the victim because he feels she should have been convicted. When a third person is killed, Erin figures out what the link is. Jamie finds a boy wandering the streets with blood on his clothes. He takes him back to his parents and can't help but wonder if there's anything wrong at their home. An astronaut who just retired, who's also a friend of Frank, comes to the New York. They meet and the man drinks very heavily and talks about his family, but Frank learns the things he said about his family are not true and tries to help him.

When a man is found wandering the street with blood all over his clothes, Danny and Baez try to find out what happened but the man says he doesn't remember. He says he's from out of town and he's with his girlfriend and that he's planning to propose to her. They go back to his hotel room and find his girlfriend dead and blood all over the room. While the guy still maintains not to know anything, Danny has no choice but to take him in. Danny's not sure what to believe. An off duty cop who was drinking comes across a robbery and stops it. Later, Jamie shows up and smells that he's been drinking and tries to help him but the Captain sees what he's doing and orders that the cop be tested. When he comes out positive, he has to face a hearing. Frank, who admires what he did, but believes in following the rules. And Erin gets a call from her daughter's school who informs her that her daughter is planning some kind of protest and if she goes through with it, she'll face suspension.

Danny gets a call to go to a project where a gang rules with fear and intimidation. Jamie finds a girl standing on the roof holding her baby, saying she can't stand their lives being controlled by street gang Los Lordes so she jumps to death with her baby. Danny later learns that the girl was someone he met when she was younger when her parents died and he said he would help her and her sister. Danny goes to her sister who is bitter that Danny forgot about them. He learns that she is now with the leader of the gang. While Jamie and his partner are walking through the project there's some shooting and Jamie's partner is hit. Frank later learns that the D.A. is not pressing to prosecute the gang so Frank goes to the mayor for help.

When an armed robbery ends with the death of a police officer, Frank makes it a mission for the NYPD to bring the suspect to justice.

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

When a gangbanger dies after Jamie chases him away from the boy he is mentoring, Jamie's conduct is called into question. Meanwhile, Baez goes undercover to get information on Danny's ex-girlfriend's fiancé who is dealing drugs from his gym.

Danny and Maria investigate a local bombing, but are met with tension and resistance from the community during the investigation. Meanwhile, Frank must deal with the political fallout when a man punches an officer who was overly aggressive in his questioning.

When Danny learns from Nicky that there's a deadly new brand of heroin hitting the streets, he begins an all-out manhunt for the distributor. Meanwhile, Frank pulls out all the stops to assist in getting the drugs off the street.

Baez gets injured while escorting confiscated drugs, so Danny goes after the drug cartel responsible. Elsewhere, 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.

Danny Reagan is accused of police brutality. Frank has to walk a fine line in the investigation and find the truth. Jamie meets a female doctor, and it makes Janko uneasy.

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

Baez is held hostage in an interrogation room by a distressed man who wants to see his daughter. Elsewhere, Garrett's son gets in trouble with the law, so Garrett turns to Frank for help, creating an ethical dilemma for the police commissioner.

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

In the conclusion of the two-part Season 5 finale, 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.

A possible serial-killer case is assigned to Danny and Baez. Erin considers becoming a judge; a mayoral candidate claims that Frank has been secretly investigating her spouse; and Eddie confronts her dad.

Danny joins the search for two escaped convicts after learning that one is someone he helped wrongfully imprison.

Camera footage appears to show Jamie committing police brutality at a demonstration; a civil rights attorney claims a rape case includes drummed up charges.

DA Investigator Anthony Abetemarco helps Erin when she is forced to take a case from a colleague, ADA Kelly Blake; Eddie and Jamie pose as an elderly couple in order to catch a gang.

Erin is overwhelmed with guilt after a man she set free is accused of killing a cop. Also, Frank and Mayor Poole continue their game of political chicken over Frank's reappointment as commissioner, and Danny and Maria investigate a case of a cop who has gone AWOL.

The newest Speaker of NY City Council, (Whoopi Goldberg), a chronic malcontent, wants to dismantle the NYPD's "Broken Windows Policy," a position Frank vehemently opposes. Erin worries when the wife of her good friend and mentor, Judge Wilson, dies as a result of DUI, and, his sentencing suddenly runs off the rails. Linda's co-worker at the hospital has a problem with her ex-husband. Linda asks Baez and Danny to talk to the parties involved and it turns into a big ordeal. Judge Wilson takes on attorneys who dare to argue with the bench (i.e. our jobs); it may be time for a Judicial Ethics Commission Complaint. Does Erin have the balls to file one?

Jamie and Danny disagree about how to handle a reckless NYPD rookie, Marcus, who is the son of Dannys friend. Also, when Erins investigator, Anthony, gets roped into a bad investment by his cousin, she offers to look into it.

An officer involved in the controversial shooting of an unarmed person 14 years prior, is up for a promotion which brings up mixed feelings from various NYPD officers, in addition to forcing Frank Reagan to make a difficult decision.

Erin's ex-husband represents the person she's trying to convict of murder.

A Mexican drug cartel targets Danny when he intercepts a shipment of several million dollars; Jaime goes after a serial killer who preys on the elderly; Mayor Poole confides in Frank that he plans to retire.

Cases this week involve (Danny) a widowed nurse that is the victim of domestic violence, (Frank) a woman that alleges corruption at the jail, and (Jamie/Janko) an illegal alien that gives birth and lives in a condemned home.

Eddie's judgment is clouded by her past when she arrests a loathed college acquaintance; Frank is hesitant to mar the spotless record of a member of the force who tested positive for marijuana.

Danny and Baez join a narcotics task force to track a drug supplier; Baez comes into contact with drugs and gets an accidental overdose; Jamie and Eddie work to protect a rehabilitated sex offender; Frank forms an unlikely alliance with Mayor Dutton.

Jamie and Eddie ask Erin to drop the charges against a man who bravely rescued a woman from a local hostage situation; Danny and Baez work a case involving car thieves and discover the leader is a mobster they've dealt with before.

Danny is forced to ask his incarcerated arch enemy for help when a convict escapes from prison; Frank tries to talk Jamie to take the sergeant's exam; Erin's plan to go on a date with her ex-husband creates friction between her and Anthony.

Danny takes a case involving a drug cartel member he believes set his house on fire; Erin is given a promotion but finds herself in a challenging situation when both Danny and Jamie ask her for help with their investigation.

Jamie clashes with Eddie and her new partner when they fail to intervene in a dispute at a convenience store; Danny and Baez investigate the death of a college freshman at a fraternity party; a sergeant accuses the department of reverse racism.

Danny goes against a direct order during a hostage negotiation; Nicky asks Erin for help when her friend is in jeopardy of losing his scholarship because of a crime he didn't commit; Frank helps a distraught officer who accidentally shot a girl.

While off duty, Danny encounters a gas station robbery in progress and is forced to use his weapon, leaving him shaken and his family and co-workers concerned; Frank learns that a top officer in his department has a dark past.

After a woman is murdered in her apartment, Danny and Baez turn to her daughter for help, but instead she complicates the investigation; someone from Jamie and Eddie's past launches a smear campaign against them.

Danny and Baez work with Texas Ranger Waylon Gates when they are part on a case to find the Lone Star Killer; after Eddie's partner mistakenly shoots an undercover cop, Internal Affairs accuses Jamie of not supervising properly.