Ash and friends are passing through a town where a Sumo Competition is about to be held. Ash, competitive as always, decides to enter the contest with his Snorlax. But will he be able to win without any training in sumo wrestling?

On the way to Olivine City, Brock's Golbat begins to act strangely and flies to a archeological dig site. A girl named Tierra is there using ultrasonic waves to help dig up a special artifact, an ancient gold mask and scepter that once belonged to a queen. Together they have the power to control any Pokemon. Team Rocket hears this and plans to steal it.