13-year-old Liffey Rivers is power-walking around the hotel lobby at the Celtic Arch Feis in St. Louis when she notices a suspicious looking man carrying a beautiful Irish dancer doll in his plastic shopping bag. An over-sized sparkling diamond tiara is perched on top of the doll's curly brown wig--but Liffey can see that the doll is wearing a traditional Irish dance school dress. Intuitively, she realizes that whoever put this dress on the doll, did NOT place the diamond crown on its head. When Liffey cannot resist investigating further, she finds herself not only trying to win a 1st place medal to qualify for her first Irish dance solo dress, but also dodging international smugglers. After a series of suspenseful cat and mouse chases, Liffey Rivers unravels the mystery of the sparkling solo dress crown.