Sofia is going to have her first Royal Slumber Party. Amber brings her to the castle's observatory, where everyone will be sleeping that night, and tells her the most important part of a Royal Slumber Party is the guests. She invited Princess Hildegard and Princess Clio, the most popular Princesses at Royal Prep, while Sofia invited her friends Ruby and Jade. Amber is shocked that Sofia would invite village girls, but Sofia tells her that Ruby and Jade are really fun to be with. Down in his lair, Cedric is visited by King Roland and Queen Miranda and is asked to put on a magic show for the girls at their party. Disgusted at having to do such a thing, he decides to use this opportunity to steal Sofia's amulet by performing a magic trick with his puppets that will make the amulet disappear right into his hands.

Amber's guests Hildegard and Clio are the first to arrive at the castle and, much to their annoyance, Sofia's guests arrive soon after. When Hildegard asks if those "village girls" are coming to their party, Amber states that Sofia invited them, causing Hildegard and Clio to turn and glare at her. Sofia promises that they'll see that Ruby and Jade are the best. After changing into their PJs, Ruby and Jade do a goofy dance while wearing pine cones in their hair and rapping. The Princess trio are astonished, but Sofia likes what they're doing so much that she runs over and joins in. Appalled, Amber, Hildegard, and Clio pull Sofia aside and tell her that at a perfect slumber party, everyone has to fit in. But Sofia disagrees, saying that the point is to have fun and she will show them that Ruby and Jade can fit in, though the princesses are unconvinced.

Sofia gives her friends Royal Makeovers to make them look like princesses, but they still don't really act like princesses. While painting fans, Ruby paints a smiley face on hers instead of roses like she's expected to, then Jade knocks over a display of the Solar System while playing pin-the-tail-on-the-unicorn. Before Amber can scold Sofia again for her frie