6 Series, 139 Episodes
The officers at the precinct drop everything to intervene when they suspect that Captain Holt is in danger after their efforts to track down Adrian Pimento's hitman take an unexpected turn
Pimento's life is still in peril, so Captain Holt calls on an old friend in the FBI to help identify the crooked agent who tried to have him killed. Santiago makes a breakthrough while undercover.
To get information on a criminal operation, Santiago has to go undercover at a women's prison and befriend one of the inmates. Captain Holt and the team plan a fake funeral to help catch a hitman.
Jeffords disapproves of Diaz's fast-moving relationship with Pimento. But the new couple's love has to be put on hold when Pimento comes to believe that someone from his past is trying to kill him.
To prove to his old precinct that he's not a joke, Jeffords enlists Peralta's help to solve a case from his past. Pimento moves in with Boyle. Santiago attends a training exercise with Holt and Diaz.
Holt allows Santiago and Peralta to house-sit for him while he visits Kevin in Paris, but mayhem ensues when Holt's beloved dog goes missing on their watch. Pimento and Diaz have a romantic fling.
The precinct gets a new detective who has just left a 12-year undercover assignment with the Mob. Boyle's latest mess lands everyone in trouble with the caretakers, and Gina directs a video for Holt.
When Peralta insults Hitchcock and Scully's work ethic at the precinct, they get involved in a dangerous investigation in an attempt to prove themselves. Holt and Boyle work on a celebrity case.
The Nine-Nine play host to detectives from nearby precinct the Nine-Eight when their station house is flooded, reuniting Peralta with his old partner Stevie Schillens, but Boyle soon becomes jealous
On his birthday, Peralta takes Santiago to meet his mother but an unexpected appearance by his father spoils his special day. Diaz and Boyle struggle with a new mandate on body cams during a stakeout.
Peralta and Santiago are excited to go on their first holiday together. Boyle and Diaz vie for the same apartment, while Gina and Jeffords help Captain Holt to survive a visit from his sister Debbie.
Captain Holt and Peralta contract mumps during an investigation, and decide to be quarantined together so they can use the time to solve the case. Jeffords has to clean up Hitchcock and Scully's mess.
Boyle and Genevieve want to take their relationship to a new level. Santiago asks Jeffords to write a letter of recommendation for her. Holt and Diaz enlist Gina's help with a difficult interrogation.
Peralta, Boyle and Gina get involved in a real-life 'Die Hard' hostage situation while doing some shopping on Christmas Eve. Santiago attempts to prove she's just as tough as Captain Holt and Diaz.
Santiago and Jeffords help Gina to prepare for an exam. Peralta and Diaz work with two Swedish detectives on an international jewel theft case. Captain Holt enlists Boyle as his squash partner.
Jeffords asks Peralta to look after his pregnant wife Sharon when she drops in at the precinct in his absence. Computer problems leave Santiago and Boyle dealing with a huge pile of paperwork by hand.
Peralta and Santiago ask Captain Holt to let them work together on a case involving a new street drug, but their personal relationship gets in the way. Boyle panics when he damages Holt's prized car.
Peralta and Boyle persuade Jeffords to join them on a weekend trip to a cabin in the woods. Holt gives Diaz important relationship advice. Santiago enlists Gina's help to prepare for a presentation.
The third instalment of Peralta and Holt's 'Halloween heist' involves a tie-breaking competition to claim the title of 'amazing detective slash genius' in which they split the squad into two teams
While investigating a serial killer, Peralta enlists Holt's help in an attempt to solve the case without the new captain finding out. Diaz and Santiago are forced to deal with The Vulture's demands.
Peralta thinks that Boyle might have found his soul-mate in Genevieve, an art gallery owner, so he tries to bring them together. Diaz deals with a case of theft within the precinct building.
The precinct gets another personnel change that could put Peralta and Santiago's budding relationship at risk, while Diaz and Gina try to convince Boyle to rethink his affection for a fellow officer
Captain Holt is transferred to the NYPD Department of Public Relations and the arrival of a new captain makes the precinct dissolve into chaos. Peralta and Santiago face the aftermath of their kiss.