What could convince our heroes to take a time-out from their journey to Eterna City? A Pokemon Dress-Up Contest where Pokemon try to imitate other Pokemon! Ash and Pikachu, Dawn and Piplup, Brock and Croagunk, even Team Rocket--they're all entering the contest in hopes of winning the Pokemon Egg prize! But will any of them be able to beat the reigning champion, a singing Chatot?
In the contest, the key is to stay in character. So when Piplup, pretending to be Weedle, gets a little too excited and uses BubbleBeam, he and Dawn are knocked out of the first round. Ash and Brock make it into second round along with Team Rocket and James wants to win the contest fair and square. But to his dismay, Jessie can't resist stealing the prize Pokemon Egg, forcing Team Rocket to make a quick getaway. Together with Officer Jenny, our heroes chase after Team Rocket so quickly that Brock's Croagunk doesn't even stop to take off its Politoed costume!
There's no doubt who'll win this showdown, especially once Mime Jr.'s Teeter Dance hits Team Rocket instead of its target. In all the confusion, Team Rocket drops the stolen Pokemon Egg. Buneary quickly catches it, Pikachu sends Team Rocket packing and everyone returns to the contest for the final results. After the judges tally their votes, the final winner is Brock's Croagunk who stayed in character as Politoed even while chasing Team Rocket! Brock accepts his Pokemon Egg, leaving him and his friends to ponder two important questions. When will the Egg hatch--and just what Pokemon will turn out to be?