Ash has reached the Pastoria City Gym, but there's no Gym battling today—the Gym Leader, Crasher Wake, is off to the Pastoria Great Marsh. He invites Ash and the gang to join him, and our heroes are spooked to see lots of Croagunk emerging from the marsh grass. Every household in Pastoria City has a Croagunk and today is the annual Croagunk Festival! Last year's festival honors went to Craig, a Croagunk owned by Hamilton. Hamilton wants Craig to marry Chrissy, Nurse Joy's Croagunk, but Chrissy isn't interested. Hearing this, Brock enters the Croagunk Festival, hoping his Croagunk will win the crown and save Chrissy from an unwanted union.

Out in the marsh, James reminisces about meeting his Carnivine while Jessie and Meowth plan to enter the Croagunk Festival with Meowth in a Croagunk costume! Meowth even excels in the first round of the Festival, a Croagunk beauty contest that leaves Dawn at a loss to tell all those Croagunk apart. The next round is a brick-breaking competition; Brock's Croagunk aces the round, but Meowth ends up with nothing more than an aching paw to show for it. So now it's Brock's Croagunk and Hamilton's Craig in the final championship battle!

The title bout is interrupted by Team Rocket's giant Croagunk Robot, which steals the Crown and both battling Croagunk. Crasher Wake left his Poké Balls at the Gym, so he calls on all the other Croagunk to stop Team Rocket. Nurse Joy and Chrissy lead the charge with Chrissy's Vacuum Wave attack, and with a little help from Ash and Pikachu, Team Rocket is put down for the count. Chrissy's show of bravery earns her the Croagunk Festival crown, and everyone celebrates by singing and dancing into the night. But come the next morning, Ash will have to face Crasher Wake at the Pastoria Gym!