An unexpected third wheel puts a damper on Jake and Amy's tropical honeymoon. Back at the Nine-Nine, Terry experiences a crisis of confidence.

Jake and Charles investigate a case of Hitchcock and Scully's from the 1980s. Meanwhile, Amy's uniformed officers and Terry's detectives fight over limited resources.

Jake and Gina attend their 20th high school reunion. Back at the Nine-Nine, Charles helps Rosa with her love life.

Jake investigates a series of car thefts that point to an old frenemy. Meanwhile, the squad defends their favorite bar from interlopers.

A promise made to a grieving mother sends Jake spiraling into obsession as he and Rosa comb the scene of a baffling murder for clues.

Holt and Jake become suspicious of a new Nine-Nine employee. Amy goes full-on Marie Kondo to declutter the bullpen.

Amy and Jake hear conflicting stories as they investigate a sexual assault accusation. Holt refuses to believe an old nemesis is really dead.

Jake helps Amy navigate the complicated relationship she has with her brother, David. Charles introduces some drama into an undercover mission involving Terry and Holt.

A visitor from Latvia causes Charles and Jake to investigate Nikolaj's family. Holt and Amy bring in famed forensic scientist Dr. Yee to help close a case for Rosa.

A missing person case forces Jake to confront his issues with therapy. Holt invites Rosa and her new girlfriend to dinner. Terry overcompensates.

While celebrating their first anniversary, Jake and Amy realize they've had a communication breakdown over a major life decision.

A burglary investigation at Kevin's university reveals Holt's hidden insecurity. Amy and Terry's efforts to raise morale turn deliciously cutthroat.

As Hitchcock and Scully microwave a lasagna for exactly 21 minutes and 30 seconds, the squad races against the clock to catch a hacker.

Gina invites Jake and Terry over to her new place. Holt takes an interest in Nikolaj's education. Rosa rejects Amy's offer of a helping hand.

Mayhem and double-crossing overtake the squad as they try to distract Terry from his lieutenant's exam by kicking off the Halloween Heist on a new day.

Jake and Boyle hunt for a serial killer under the watchful eye of Commissioner Kelly. Terry learns that more money does indeed bring more problems.

To right a wrong, the Nine-Nine teams up with the worst of the worst of the NYPD. Terry sinks into deep denial about his future.