Candace switches places with a princess who looks just like her, but the ongoing antics of Phineas and Ferb prevent her from enjoying the royal luxuries, even for a day. Meanwhile, Phineas and Ferb enlist the princess to help them build a giant jukebox filled with live bands, and Dr. Doofenshmirtz plans on using his Claw-inator to ruin his brother’s dedication of the new Danville Opera House.