Monica and Chandler enter Central Perk and Monica tells the others that they are having a Halloween party and they must all wear costumes. Joey and others aren't too pleased about having to wear costumes. Ross agrees that he will invite Mona to the party as well.
Phoebe meets Ursula on the street. She asks her what she's doing and Ursula says she is having a wedding and invites her. Phoebe also invites Ursula to the Halloween party.
Rachel arrives at the party and hears some kids trick-or-treating. She says she will be in charge of the candy that night because she is having strong maternal instincts and loves children. She sees to the trick-or-treaters, complimenting each one. Phoebe suddenly enters the room dressed as Supergirl and has a small showdown with Monica, who is dressed as Catwoman. Chandler comes over dressed as a big pink bunny which he doesn't like saying it is not the right color. (He was hoping to be more like the Velveteen Rabbit) Joey then enters the room without a costume, but says he is dressed up as Chandler. Joey then makes some impressions of Chandler.
A small girl knocks at the door trick-or-treating. She keeps doing more displays causing Rachel to give her more and more candy, she then says she loves Rachel and Rachel just gives her all the candy.
Ross enters the room dressed up in a big potato with antennae. When the others can't guess who he is he reveals he is 'Spud-nik'. Joey thinks he is a doodie.
A mysterious man suddenly walks into the room and slaps Phoebe on the ass and tries to kiss her, mistaking her for Ursula. Phoebe isn't too bothered, being quite attracted to him. He reveals himself to be Ursula's fiancé.
Monica comes over to ask Joey who would win between her and Phoebe, Joey says Phoebe would win and so would Rachel. Phoebe comes over and says how sweet Ursula's fiancé is, Monica believes she has a crush on him.
Rachel answers the door to a kid but has no candy left and she has also given out all the money so she starts writing out checks.
Mona arrives dressed up as a nurse and instantly guesses that Ross is spud-nik.
Joey and Monica continue to consider who would win in different fights and ask themselves who would win between Ross and Chandler, they both come to the conclusion Ross would win.
Ursula arrives and her fiancé meets her, they speak about how good they are together. He says they have only been together for two weeks and that they have lots in common. Phoebe realizes that Ursula has been lying to him.
Chandler and Ross begin to get into a minor argument and Joey says he might get the answer to who would win in a fight. Chandler gets upset when Monica believes Ross would win and Ross sparks off a funny fight when he says she is right. Monica intervenes and Mona decides that the only way to resolve it is with an arm-wrestle.
Gunther arrives at the party with the candy Rachel needs. She then answers the door to a kid who wants money instead of candy. The kid and Rachel get into an argument telling each other to shut up. The kid runs off crying causing Rachel to chase after him.
Monica is trying to persuade Chandler not to go through with the arm-wrestle but she is unable to influence his opinion.
Outside the apartment Phoebe meets Ursula and tells her what she is doing is wrong. Phoebe gets angry with her.
The arm-wrestling competition begins and seems intense to begin with, the arm-wrestle lasts ages and there is no end in sight. They both try to make each other quit; Chandler lets Ross win so he can impress Mona.
Ursula's fiancé comes back for Ursula's bag and Phoebe can't let him go ahead with the marriage saying she has been lying. He feels stupid for what he has done. Phoebe and him begin to have an intimate moment but are interrupted.
Rachel returns to the apartment and tells Joey she is terrible with children. Joey says it's just because it is Halloween and that she is good with kids generally.
Monica and Chandler are talking about him losing at the arm-wrestling competition. Chandler says he let Ross win, but Ross says it's a lie. Chandler wants to prove how strong he is so he and Monica have an arm-wrestling competition but he is in the same position as last time.