All Torkoal, No Play
Ash and friends are walking through the Valley of Steel on their way to Petalburg Gym when they encounter a Torkoal being attacked by a Skarmory and several Magnemite. May's Skitty and Torchic drive the Steel-type Pokémon away.
The Pokémon of the Valley of Steel turn out to be very territorial, and both Torkoal and the kids have put themselves in danger by trying to cross the valley. Regardless, they decide to press on.
Team Rocket is in pursuit, though at first the trio is attacked by Skarmory and later Steelix. They are sent blasting off and nearly hit Ash and his friends on the way down, falling into a chasm instead. May tumbles off the edge, and Ash and Torkoal work together to save her. They are attacked by a Magneton, which Torkoal sends flying using Flamethrower.
Magneton is found by the Steelix, who then goes looking for Torkoal and the kids. When they meet, it turns out that Torkoal came to the valley looking for a fight with this powerful Pokémon. The two begin to fight, with Ash directing Torkoal. Steelix has the advantage until Torkoal uses Overheat, knocking the giant Steel-type out.
Torkoal joins Ash's roster of Pokémon, and the gang leaves the Valley of Steel.