With Oreburgh Gym Leader Roark as referee, Ash starts his 3-on-3 Gym battle against Byron, Canalave's fossil-loving Gym Leader. Byron's first Pokémon is the Steel-and-Psychic Bronzor, so Ash sends out Chimchar, a Fire-type Pokémon. But Bronzor's Ability, Heatproof, helps protect it against Chimchar's Fire attacks, and then it uses Rain Dance to rain on Chimchar's parade! Chimchar refuses to give up, and uses Flame Wheel in a head-on charge against Bronzor's Gyro Ball—the hit knocks out Bronzor, but Chimchar barely manages to stay on its feet!

Elsewhere in the Gym, Team Rocket sneaks in to steal Byron's fossils... and the contents of his fridge! However, Byron's Omanyte, Omastar, and Kabuto blast the intruders back where they came from. Over on the battle floor, Steelix takes on Buizel; Buizel should also have a type advantage, but it can't get past Steelix's Screech. Before Ash can counter, Steelix hammers Buizel with Iron Tail, and Buizel's fight is done! Ash sends Chimchar back in to knock out Steelix with Flame Wheel, and now it's faced with Byron's prized Bastiodon.

As Team Rocket sneaks back into the Gym, only to be tossed out again by Byron's Armaldo and Cradily, Chimchar proves too exhausted to defeat Bastiodon. Now it's up to Ash's Gliscor, making its Gym battle debut! It takes a pummeling from Bastiodon, but it keeps fighting and uses its aerial advantage to get past Bastiodon's defenses. That lets it knock Bastiodon out with an explosive Fire Fang! Gliscor's first Gym battle is a success, and Ash is now the proud owner of a Mine Badge!