While on-route to Vermilion City, Ash stumbled upon a Charmander sitting on a rock in the pouring rain. It's flame on its tail was almost completely out and it looked like it was in bad shape. Ash Ketchum was always disappointed that he couldn't get a Charmander from Professor Samuel Oak on the first day of his journey and he was extremely disappointed. Ash Ketchum tried to catch the Charmander but eventually he came to realize that it was already owned by another trainer and that it was probably waiting for its master to return. Ash Ketchum decided to leave the Charmander and then arrived at the local Pokémon Center where Damian was boasting that he no longer had a Charmander as he left it at the mountain pass.
Ash Ketchum realized that the Charmander that Damian was talking about was the same one that he passed on the mountain pass on the way to the Pokémon Center. Ash Ketchum decided to return back to the mountain pass to rescue the Charmander. It's tail was almost completely out when he arrived but he quickly took it to Nurse Joy who treated it. During the night, it returned to the rock on the mountain pass to await for its trainer Damian to come and get it.
Team Rocket ended up encountering Damian's Charmander and were quite impressed with its strength. Damian overheard Team Rocket's comment about his Charmander being strong and decided that he wanted to keep it. Ash Ketchum managed to convince Damian's Charmander that it had waited enough for Damian and he had abandoned it once and would probably do it again if the circumstances changed again. Ash Ketchum gained the trust of Damian's Charmander and ended up getting it.