Guest Stars: Dirk Blocker as Hitchcock, Joel McKinnon Miller as Scully, John Ross Bowie as Sister Stevie, Phil Abrams as Uncle Bob, Christina Brown as Sexy Robot, Kanin Howell as Banana Perp, Justin McCully as Tarzan, Nick Nicotera as Royal Baby #2, Kat palardy as Raggedy Ann, Jimmy Smagula as John Perpton, Miles Platt as Young Jakes, David Carmon as Royal Baby, Matthew Daniell as Zombie Drug Dealer, Jared Lynton as Gorilla Drug Dealer
Writers: Lesley Arfin
Director: Dean Holland
Terry: I'm a detective. I will detect.
Charles: Santiago, I know that you hate Halloween, but stick with me, and I promise you, you will love it.
Amy: Can you magically make everyone kind, sober, and fully dressed?
Jake: "Kind, sober and fully dressed." Good news, everyone. We found the name of Santiago's sex tape!
Charles: What is all this?
Amy: You know how I think Halloween is for jerks? Well, this Halloween, I was the jerk. I'm sorry about tonight.
Jake: "I'm sorry about tonight." We found the title for Santiago's follow-up sex tape!
Amy: We got egged. Some of shell got in my contacts, and my hair, and my mouth, and my bra.
Jake: Can't tell if that's hot or not.
Amy: Not hot. Egg shell in my bra is not hot.
Jake: Well, it's kinda hot. Boobs go in a bra.
Terry: So, I called your school, and I managed to get a hold of one Sister Bernadette.
Rosa: I remember that old bag. She was my favorite.
When a fight between costumed criminals breaks out in the bullpen, Amy complains about Halloween. Boyle shows up in his Halloween costume, but nobody can work out who he's supposed to be - except a criminal who recognizes him as celebrity chef Mario Batali.
In the briefing room, Jake explains the holding cell is full. Holt says he needs two officers to go undercover at a Halloween party, so he gives the assignment to Boyle, who's already in costume, and Amy. Boyle promises to make Amy love Halloween.
Jake arrives back at the precinct with his first Halloween arrest. When Jake claims he'd make a better criminal and that none of the squad could catch him, Captain Holt says he's certain Jake would be caught. Jake challenges the Captain that he could steal his Medal of Valor by midnight. If Jake loses, he will work five weekends without overtime, while if he wins, the Captain must do his paperwork for one night and publicly proclaim that Jake is an amazing Detective/Genius. Captain Holt agrees to participate.
Rosa takes a mugging victim who is dressed as nun to Sergeant Jeffords. When the victim, who was mugged by somebody dressed like the Royal Baby, complains that Rosa keeps laughing at him, Rosa lets slip that she wanted to beat up nuns when she went to catholic school. Sergeant Jeffords is surprised to learn something about Rosa because she's so mysterious and tough. Terry hypothesizes that Rosa is actually a big softy who probably read a Maya Angelou poem at her graduation. When Rosa tells him she didn't graduate but won't tell him any more, Terry vows to find out more.
When Jake goes to Gina with an arrest file, he wants her to help rob Holt of his medal. Gina tells Jake that the Captain has a meeting downstairs in ten minutes. Elsewhere, Amy is unhappy with her skeleton costume as she and Boyle approach the Halloween party. When Amy sees a partygoer drinking vodka from an open container, she flashes her badge and blows their cover.
Back at the precinct, when Captain Holt hears noises coming from the ceiling, he immediately asks Jake if he's up there. Captain Holt tells Jake he's planning on taking down his Medal of Valor and placing it in a safe whose combination is only known to him, which is in a locked cabinet to which only he has the key. After the Captain leaves for his meeting, Jake falls through the ceiling.
Amy and Boyle arrive back at the precinct after being egged by the partygoers. The rest of the squad don't believe Jake can win his bet. Sergeant Jeffords says Captain Holt is a genius who has had Jake's number at every turn. Later, Rosa and Terry watch a line-up of people dressed up like the Royal Baby, looking for the mugger. Terry is still wondering why Rosa was kicked out of catholic school, but she's refusing to tell.
Captain Holt goes to Gina for her help in deciphering Jake's handwriting on an arrest report. When the Captain goes to his office, he finds Jake dressed as a janitor. After Holt stops him before he can retrieve the Medal of Valor, Jake claims it was a gambit designed to fail. Meanwhile, Boyle and Amy made it to the Halloween party undercover, but Amy is still not enjoying it. Amy spots a drug deal going down, so they chase the suspects.
Back in Captain Holt's office, he notices feathers being blown out of the air conditioning vent. When he goes to the next room, he finds Jake trying to put pigeons into the vent. Captain Holt tells Jake he's losing the bet, badly. When Boyle goes to Amy after she's finished logging the drugs, "Amy" accidentally speaks and reveals it's Hitchcock in the costume. Amy paid him $50 to take her place for the rest of the night.
Jake goes to chat with Gina, sad that he's losing the best. Gina tells Jake not to give up. Captain Holt was listening on the phone the whole time. Boyle goes to confront Amy about paying money to get out of working with him. Amy says she had to as it's been awful and Halloween is the worst. Boyle explains that everything Amy hates about Halloween is what makes it great.
Jake calls the Captain out of his office. The Royal Babies then put on a dance show in an attempt to distract the Captain while they steal his key. Holt finds Jake in his office before he can use the key. Jake tries to call off the bet, but Holt says no.
Sergeant Jeffords goes to Rosa to say he called her old school, who said she was a model student. Rosa tells him she transferred out to ballet school. If Terry tells anybody that she was a talented classic dancer, she will break his face. Meanwhile, Amy goes to Captain Holt to tell him that Jake was arrested as he attempted to scale the building.
In the interrogation room, Captain Holt tells Jake that even though he knew he wouldn't win the bet, his performance tonight has made him question just how good of a detective Jake is and, frankly, how smart he is, as well. Captain Holt is amazed that Jake thinks he can still win the bet when he's handcuffed to a table in a locked room, five minutes before the deadline.
Jake then explains how he got the entire squad to help him get the Captain's medal. After Holt caught Jake dressed like the Janitor, Rosa snuck into his office and picked the cabinet lock. Jake then created a diversion to get Rosa out of the office, unseen. While Jake distracted the Captain with the pigeons, Terry and Amy broke into the Captain's office and opened the window. While the Royal Babies distracted Holt, Terry stole his phone, which the Captain didn't notice in his attempts to locate the keys. Charles dusted the phone screen for prints, revealing his four most-used digits - his passcode, which Jake assumed he would also use for the safe. When Amy told the Captain that Jake had been arrested, Boyle then climbed in through the open window in Holt's office to try break the safe. Jake tells the Captain to open the door, where Boyle is standing with the medal.
When the Captain wonders how Jake got the whole squad on side, Jake explains that he offered to do all their paperwork - course Holt is now doing all of Jake's paperwork. The Captain leaves Jake chained to the desk in the interrogation room.
Terry calls Boyle to the briefing room where everyone is in costume. Amy apologizes to Boyle. Before the squad head out to a bar, Captain Holt publicly praises Jake, before going to do all his paperwork.