Jake and Captain Holt prepare for their annual Halloween bet. Jake promises the Captain that he'll do 5 weeks of overtime for free if he can't get the Captain's watch off his hand by midnight, while Holt again has to call him an amazing detective and do his paperwork for a week.
Jake hires a pickpocket (Fingers) and employs the entire precinct in an intricate plan to replace Holt's watch with a replica. The plan is successful until Fingers refuses to return the watch.
Charles and Jake head off to find Fingers, who cons them into giving money to get the watch back, which he reveals he hid in Jake's care. Jake's car promptly gets towed for parking in front of a hydrant. He and Charles try to chase the car, but get separated by a crowd of people in costume getting on to a party bus.
Jake gets a ride on the bus to the impound, but when he gets there, his wallet and badge are missing, and they refuse to give the car back. He climbs the fence, falls and hurts himself, only to see the car being lifted off as he gets arrested for trespassing.
He's taken back to jail at the precinct, where it's revealed that Captain Holt was the mastermind of the entire evening, having planned the whole setup since last Halloween.
In the meantime, Gina was being chided for not helping out at the precinct, only to find out that she's going to night school to finish college and having trouble balancing her time among school, work and dancing.