Ally is trying to come up with a costume idea for a work party she forgot about until last minute. On the phone with her mom, she comes up with the idea of going in one of those big baby costumes. She heads out to the store only to discover it's been closed. Back home with no costume and no clue what to do, she gives her work friend, Joy, a call. Joy says she can help and will be over shortly. But first, she makes a call to Ally's crush, Nick.
Ally doesn't know that the guy at work she's been crushing on is Joy's long-term boyfriend. So Joy decides to use this was a payback, of sorts. She tells Nick what Ally's plan is but wants him to watch her. When she heads to the bathroom, he needs to go up to her and just keep talking to her non-stop.
Joy shows up to Ally's place with some cloth diapers and a pink coverup. Joy helps Ally, or as she takes to calling herself, BabyAlly. Once BabyAlly is dressed Joy realizes there's a few things missing. For instance, she needs milk to go in her bottle. BabyAlly tries to get her pants on, but because her butt is now several sizes bigger she can't get her pants on. Joy says not to worry about it, after all, she is about to go to work in just that. BabyAlly agrees and the two head out.
Coming back from Target BabyAlly is now second guessing her costume because some girls at Target kept snickering at her in line. Joy reassures her saying it's a great costume and she bets once Nick sees her he won't be able to stop talking to her. BabyAlly is back to being all giddy and is looking forward to the night. She tells Joy how happy she is she has a good friend like her to count on.
Back from the party and BabyAlly is crushed. Joy doesn't understand why she's so upset, she got to talk to Nick all night long. BabyAlly says yes, she got to talk to Nick all night but she also wet her diaper while talking to him! She went to go to the bathroom and he started talking to her and she didn't want to leave and he just kept talking to her so she just used her diaper. But she thinks Nick might have noticed and now will never want to date her.
Joy calms her down and tells her she talked to Nick. Yeah, he kinda could tell she was wetting herself but she told him that Ally has bladder problems and can't help it. See, as long as Nick thinks Ally has bladder problems then he won't tell anyone and she can keep her job and everything else. Ally realizes this means she's going to have to wear diapers to work for months, if not years, to keep this one night a secret. Joy then reminds Ally that Nick could still go on a date with her so she better go get herself cleaned up.