Nancy and her two best friends, George and Bess, are so excited! They have been invited to Deirdre's sleepover party! There will be pizza, cake, and even a pajama fashion show. But the most exciting thing is that the party has a City Girls doll theme. All of the guests are bringing their dolls with them!

But then Deirdre's City Girls doll -- Hollywood Heather -- goes missing. Is her sleepover ruined? Or is there a detective in the room who can make sense of this mystery?