Nancy, Bess, and George are all taking ballet classes with Mr. McGuire, a former professional dancer, and random kids like Gregory, Deirdre, her best friend Grace, and Andrea. Gregory offers Bess some cookies and busts up laughing when she tries to eat one because they're fake cookies he took from his sister's play kitchen. He loves playing pranks on all the girls.
Mr. McGuire comes in with some big news: the “glass” slippers he had specially made for the big recital just come in and he wants to show them off. Gregory launches one at Bess who freaks out when it drops because she expects it to shatter. The shoes are actually made from a type of hard plastic. Mr. McGuire tells them that no one can touch the shoes and yells at Deirdre for even trying to take photos.
The other big news is that Autumn, the girl picked for the lead role, hurt her leg and can no longer dance. That makes Andrea, the understudy, the new lead dancer in Cinderella. Nadine, another dancer, freaks out. He had a hard time choosing between the two of them as to who would be the understudy but eventually picked Andrea. Nadine thinks she should get the role. This really just serves to set up some suspects for when the glass slippers go missing.
Andrea asks Nancy and her friends, who made up a mystery solving club called the Clue Crew, for help. They find a piece of paper with the word “taille” and the number 38 on it. George does some internet sleuthing and finds out that it's the French word for fall. They also see Gregory with his dog and looking all suspicious.
Their biggest break comes when they find that Deirdre posted a photo of the shoes on her blog but the photo was taken outside. Deirdre denies taking the slippers, but Grace breaks down and admits that they “borrowed” the slippers to take the pair outside for a picture. Gregory shoes up with his dog again, and a rhinestone falls out of his bag, which looks just like those used on the slippers. He claims that he never saw it before and willingly gives it to Nancy, but his dog seems super interested in it.
Nancy then discovers a barrette with what looks like a lightning bolt on the top. She thinks it looks like an “N” and takes it to Nadine, but Nadine denies that it's hers and says she only wears cool barrettes. When doing her costume fitting, Nancy realizes that the costume designer is Mrs. Z and that she always wears things in her hair. The barrette belongs to her, and she says she lost it when moving some set pieces.
Cut to Gregory walking around and looking really weird. When Nancy confronts him, he finally admits that he stole the slippers. He just wanted to make everyone freak out for a little bit before revealing it was a prank but then the slippers went missing. When he says he put them on a giant ice cream cone, Nancy remembers that there was a cone used for an old show.
They all run upstairs where Mrs. Z put the old set pieces and find the missing slippers. Mr. McGuire is super happy to have them back because he spent a lot of money on them or something. The show goes off without a hitch, and Nancy loves seeing her friends dance.
*Deidre Shannon is in this book and apparently hated Nancy as much when they were kids as she does when they become teenagers. It's just really weird to me for her to be in all the newer books when she wasn't in the older ones.
*Deidre has her own website called Dishing With Deirdre, which seems really weird because these kids are way too young for that.
*Andrea offers to give the girls her allowance as payment, but they turn her down because they just like solving crimes for fun.
*Is it a little weird that George is not only taking dance lessons but also super excited about them?
*Nancy has a role of a mouse in the show LOL.
*This is actually the first book I ever read from the Clue Crew series, and I thought it was really cute!