Jake isn't sure what to think when an unstable detective (Jason Mantzoukas) returns to the Nine-Nine after being under cover for years; the precinct's custodian takes issue with Charles' rebellious behavior; Holt asks Gina to direct a video.
When Jake insults Hitchcock and Scully's work ethic in the precinct, they force their way into one of his cases in attempt to prove themselves.
Chaos ensues when the nine-nine is forced to share their station with the nine-eight precinct while their station is unavailable. Meanwhile, Boyle becomes jealous of Jake's old partner, who is an officer in the precinct.
On his birthday, Jake plans to introduce Amy to his mother (Katey Sagal), but he is surprised by the appearance of his father (Bradley Whitford); a new mandate involving body cams causes problems for Charles and Rose during a stakeout with Terry.
When Jake and Amy go on their first vacation together on a cruise ship, they run into an adversary; Gina and Terry help Capt. Holt when his sister (Niecy Nash) visits unexpectedly.
Captain Holt and Jake contract the mumps during an investigation and decide to be quarantined together. Rosa tries to help Boyle mourn, and Terry cleans up Hitchcock and Scully's mess.
Charles' ex-wife tries to interfere with his relationship with Genevieve. Amy asks Terry for a recommendation letter. Holt and Rosa turn to Gina for help with a case.
Terry must leave his family celebration on Christmas Eve to save Jake, Charles and Gina from a real "Die Hard" situation; Amy tries to prove that she is as tough as Rosa and Holt
Things get competitive when Jake and Rosa work on an international case with a pair of Swedish cops. Terry and Amy offer to help Gina get ready for a test, and Holt asks Charles to be his partner in a squash tournament.
Terry's wife goes into labour sooner than expected. An Internet outage forces Charles and Amy to process all paperwork by hand, and Holt has an encounter with an ex-boyfriend.
Jake and Amy's relationship gets in the way as they work a case involving a new street drug. Charles panics after damaging one of Holt's prized possessions, and Terry teaches Rosa about discipline.
Jake and Charles take Terry on a camping trip to help him relieve stress. Amy enlists the help of Gina in trying to convince the NYPD to purchase a product she invented as a child. Meanwhile, Holt tries to help Rosa break up with Marcus.
Holt and Peralta compete for the title of "amazing detective slash genius" in their third annual Halloween heist
Jake asks Holt for help keeping a case involving a serial killer under the radar. A former adversary makes demands of Amy and Rosa, and Terry develops a new obsession.
Jake thinks an art gallery owner named Genevieve (Mary Lynn Rajskub) is Boyle's soul mate and tries to set them up on a date; Rosa tracks an inter-precinct theft; Holt asks Amy for help with an image campaign.
Another personnel change could threaten Jake and Amy's burgeoning relationship; Terry helps Holt with a public relations matter; Gina and Rosa hope to change Charles' mind when he falls for a fellow officer (Archie Panjabi).
After Holt is transferred, the precinct's new captain arrives, creating chaos; Amy and Jake face the consequences of their kiss.
When Jake and Amy go under cover to catch an identity thief, the investigation brings them closer.
When Wuntch lets Jake work his dream case, Holt worries she is setting them up to fail. Meanwhile, Terry hopes to get his girls off the wait list for a magnet school by hosting a field trip.
Jake is jealous when a detective from another precinct wants to ask Amy out on a date. Linetti and Boyle try to keep Jeffords from taking a job with a private firm, but captain Holt seems to be pushing him out the door.
Jake is badly injured trying to chase a suspect, but he refuses to take time off from the job. Holt and Rosa have an awkward dinner date with their significant others, so they invite Amy and Gina along as well.
Amy and Rosa investigate Jake's claim that somebody is trying to sabotage him and get him fired. Boyle partners up with Hitchcock and Scully to solve a case. Captain Holt refuses to lie with Terry about attending Gina's dance performance.
Jake's mainly absentee father, Roger (guest star Bradley Whitford), comes to town to spend some time with his son. Jake can't wait to see him, but Charles is skeptical of Roger's intentions. Meanwhile, Holt tasks Amy, Terry, Gina and Rosa with an impossible brain teaser in exchange for Beyoncé tickets.
It's the day of Gina and Charles' parents' wedding, and the whole squad is given a job to fulfill for the ceremony. However, Jake and Amy get sidetracked chasing a criminal, and Terry struggles to officiate the wedding.
Peralta sets out to prove that--for once--he is not the source of Captain Holt's bad mood. Boyle apprehends a notorious bank robber, who turns out to be a harmless-looking old man whom nobody else believes committed the crime.
Jake is heartbroken over Sophia, but his spirits are lifted when the squad is invited to a Homeland Security terrorist training simulation.
Jake tries to impress Sophia's boss. Gina refuses to give her blessing to her mom's engagement. Holt faces a difficult decision.
Jake goes to great lengths to keep Terry's secret from the rest of the precinct, and Amy gets her chance to partner up with Captain Holt.
The precinct's annual getaway to Boyle's beach house is ruined when Holt guilts Peralta into inviting him along for the festivities.
Jake and Boyle go on a stakeout and tensions rise between the two, Rosa shows interest in Holt's nephew, and Terry writes a book for his daughters. Santiago and Gina are displeased when they assume the characters in the book are based on them.
