Season 4

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. However, tensions run high in the Reagan household when Erin drops the charges and releases the suspect due to lack of evidence.

When a famous movie star who shadowed Danny for research on his next role is stabbed, Danny goes to his aid but must keep the crime on the down-low due to the celebrity's status.

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

A teen girl dies after she is seemingly pushed in front of a subway car by a homeless man. Frank is irritated because he has to meet the new inspector general (Bebe Neuwirth).

When Danny and Baez suspect a little girl might be the victim of a kidnapping, the girl’s mother denies it, but her story doesn’t add up. Meanwhile, Frank pays a visit to a priest, a counselor to the NYPD, who was arrested on a DUI charge.

Jamie's conduct is questioned when a suspect he was pursuing is fatally injured. Baez goes undercover to investigate a drug dealer — the fiancé of Danny's ex-girlfriend.

When an officer is accused of using excessive force on a suspect, Frank finds his department under scrutiny from the community and the mayor. Danny and Baez investigate the murder of a Wall Street securities trader who was deep in gambling debts.

Frank is put in danger when his dinner companion, mob lawyer Angelo Gallo, is shot. Danny is a juror in a murder trial.

Danny and Baez investigate a homicide in which Baez’s estranged brother, a former drug addict, is the lead suspect. Frank learns one of his most highly decorated officers, a German Shepherd in the K9 unit, is being accused of brutality. Henry investigates the widow of a former NYPD pal who might have had a hand in her husband’s death.

Danny and Baez investigate a local bombing but meet with tension and resistance from the community during the investigation. Frank must deal with the political fallout when a man punches an officer who was allegedly too aggressive in his questioning.

Danny’s loyalty is tested when he is assigned to the case of a childhood friend, Mickey, who is under investigation for having ties to an infamous mob family. Frank gets word that crime is on the rise due to a recent judicial ruling about the legality of the “stop and frisk” policy.

Danny is after the distributor of a deadly new street drug.

Danny and Baez search for a Marine veteran who may have PTSD. A woman seeking justice for her murdered daughter catches Frank off guard during a press conference.

A popular drag queen and reality-TV star is found dead in a park. The mother of an accused man abducts Erin.

A kidnapping investigation brings back bad memories for Danny, who worked a similar case years ago. Frank and Inspector General Peterson butt heads.

When Danny takes a call from a woman who is threatening to kill herself along with the man who killed her parents in a drunk driving accident, he rushes to find her. Frank accompanies his grandson, Sean, on a class field trip and struggles to get the lead chaperone to loosen the reigns so the kids can have fun.

Danny and Baez search for teenagers who have been randomly punching unsuspecting people in the head, including a pregnant woman. Frank worries that promoting an officer will be viewed as favoritism.

A woman dies after undergoing plastic surgery, so Danny and Baez try to figure out what happened. Frank asks Jamie to solve a cold case. Erin explores the world of speed dating.

A college professor involved with a questionable scholarship program is murdered. Danny is investigated for ethical and procedural violations.

Erin investigates a case involving a police officer accused of killing a suspect in custody. Jamie encourages his partner Eddie to forgive her father.

After a detective from Danny's precinct is killed while working undercover, Frank goes above and beyond to find the killer only to discover that the victim held a big secret. Jamie and Eddie help Nicky track down a homeless former classmate.

Danny uncovers shocking information while investigating a case against orders.