Timmy needs to raise money for tickets to see Crash Nebula on Ice, so he starts a lemonade stand. But his lemonade tastes terrible! That's when Cosmo, stupidly, puts his sweaty socks into a glass. Believe it or not, it makes the lemonade taste a lot better. But it also starts granting everyone's wishes!
Timmy tells Trixie Tang that he has a great gift for her, so he can be invited to her party. Obviously, he's lying. Later that day, Timmy and Cosmo start making of girls, and Wanda becomes so angry she turns Timmy into a girl. Timmy decides being a girl can help him/her figure out what Trixie would like for her birthday, so he/she goes off to the mall...but not without revenge on his godparents for turning him into a girl...he wishes Cosmo was a woman and Wanda was a man.
Timmy thinks Cosmo and Wanda have it easy being godparents, and vice versa. To prove each other's points, Timmy becomes a fairy and Cosmo and Wanda become normal kids. But Timmy can't control his magic and has to undergo training from Jorgen von Strangle, and Cosmo and Wanda have a tough time dealing with Timmy's parents and school.