When it's scurvy-prevention day at school, Mindy parades in her float in anticipation for the Little Miss Scurvy beauty pageant, and she insults Mandy, telling her she is ugly. To prove her otherwise, and with Principal Goodvibes encouragement, Mandy considers entering the pageant. Naturally, Billy and Grim can't believe Mandy when she tells them about the idea, but finally they decide to help her. Then, Grim calls for Crabina, the Underworld's greatest makeup artist, to give Mandy a complete makeover. Crabina is shocked by Mandy's sour attitude, so she sets up principally to make her smile. At the pageant, Mandy has a real chance at winning the contest, but she still refuses to smile during her heart-warming musical number. Ultimately she smiles, but this event is so strong and powerful that it alters the natural order of things, and The Grim Adventures universe transforms into the The Powerpuff Girls universe, with Billy, Mandy and Grim turning into the three Powerpuff girls, Irwin turning into Mojo Jojo, and Professor Utonium guest starring as himself in a cameo.