It's baseball season and Timmy's friend Chester is the worst player on the team, again. So, for the first time, Timmy makes a wish for someone else and wishes that Chester was the best baseball player ever. To find the perfect birthday gift for Trixie, Timmy must learn how a girl thinks so he becomes a girl for a day. But things really get complicated when AJ and Chester fall in love with Timantha. When Dad sends Timmy's threat-mantic e-mail to Trixie, Timmy turns himself into data and dives into the Internet to retrieve it! After accidentally entering Mr. Crocker's computer, Timmy discovers that what happens next threatens Cosmo's and Wanda's very existence.