After losing someone close, the Reagans join forces to bring down the gang leader responsible. Danny focuses in on the gang leaders' girlfriend as a way to find him. Frank is hit hard by a second loss.
Danny's upset he couldn't help a young woman who commits suicide. The Reagan family looses someone close due to the gangs in the projects.
Danny discovers a disoriented man in the park covered in his girlfriend's blood with no memory of what happened. After a strong narcotic is found in the man's blood, Danny must figure out what transpired. Jamie's good deed helping out a intoxicated off-duty officer gets him in trouble.
A drug deal gone bad results in two deaths and a wounded accomplice. When Danny gets to the hospital Linda won't allow him to question the suspect until after surgery. A battle ensues between Danny and Linda when the suspect dies in surgery.
Danny investigation into the murder of a religious young woman reveals a secret that shocks her family. Frank and the 12th Precinct must contend with a disgruntled ex-police officer who is targeting those he holds responsible for his current situation.
Danny must figure out the common denominator when the same tragedy happens to seemingly random people. Frank helps a friend deal with his alcoholism.
Danny's latest case involves a pair of "Bonnie and Clyde" bank robbers. Frank contemplates dating a woman who's a friend of Erin.
Danny and Erin collaborate on a cold case involving a girl who was attacked by her boyfriend who was never convicted. A friend of Jamie's sues Danny's friend after an injury at a pick-up basketball game.
Danny's assigned to take an anger management class after his handling of a case involving a 10-year old victim. Politics are the order of the day as Frank tries to help a young Turkish woman avoid persecution.
A Hasidic community is under investigation by Danny when the successor named as Hasidic Grand Rebbe is murdered. Henry reveals a family secret to Frank.
Danny investigates when a man with multiple rat bites is thrown from a moving car. Curtis Swint, a bigoted radio host, broadcasting from New York City proves trying for Frank.
The Reagans unite behind Danny when he's arrested after a stop of his vehicle reveals a bag of cocaine in the trunk.
After an on the job incident, Jamie meets with a NYPD psychologist to deal with his emotional aftermath. Meanwhile, Erin questions Mayor Poole on the witness stand during a trial with a very no-nonsense judge presiding.
Danny and Kate investigate what might be an environmentalist killing motorists in their gas-guzzling cars. Sean's life hangs in the balance after a bicycle accident.
Linda helps out Danny and Kate when she overhears important information related to their shooting case. Jamie is determined to track down the person who attacked Henry at an ATM.
Danny investigates the murder of a college student who may have been dealing drugs. Jamie reconnects with a former law school classmate and wonders if he made the right career choice. Nicky's growing up and Erin has to learn to give her some freedom.
A stabbing death has Danny investigating a voodoo community. Garrett discusses a dark secret with Frank. Jack and Sean head out with Erin and Nicky for some trick or treating.
Danny helps out Erin by playing bodyguard to her key witness after he's almost killed in a hit and run. Jamie and Vinny bust a drug operation.
Danny's on the hunt when a Malaysian drug lord takes a recently decorated NYPD detective as his hostage. When Henry goes on a ride-along, Jamie is introduced to other ideas about how to do his job.
Danny and Jackie's investigation into a drive-by murder is reassigned when they are needed to protect a central American president who's been targeted for assassination. Jamie begins to question his new partner's methods.
When two separate murder victims are found to be part of a group charged with gang rape, Danny considers the possibility that the same person killed them both. Erin faces off in court against her ex-husband Jack Boyle.
Danny and Jackie investigate when an injured woman recants after making a domestic violence claim against a councilman, who also happens to be a friend of Frank's. Danny has to adjust when Linda goes back to work.
A dangerous criminal that Danny put away seeks his revenge by kidnapping Jackie. Jamie gets a new partner. A young officer accidentally shoots an innocent man.