Ash, Misty, and Brock have been on the road for ten days, and still haven't gotten to Vermilion City. They stop for a rest and check their map. After Brock pulls a little prank on Misty, and gets a kick in the face in return, Misty starts to take a walk. She is stopped short by a huge shadowy Pokémon. It turns out to be Charmander on a rock. The flame on its tail is very low, an indication of how weak it is, as Brock points out. Ash tries to catch it, with the intentions of taking it to a Pokémon Center. Unfortunately for him, Charmander doesn't want to be caught. Through Pikachu, he explains that he already has a trainer, who is coming back for him. Brock advises Ash that it is probably best to leave it there, and they all leave.
They reach the Pokémon Center just as it starts to rain. Misty gets all of them some soup, but Brock doesn't touch it. He explains that he's worried about the Charmander, and hopes that his trainer picked him up. Just then, they hear a trainer nearby bragging about his many Pokémon. When a listener asks him about his Charmander, he says that he left it behind in the forest since it was so weak. Brock stands up, takes the trainer (whose name is Damien) by the shirt, and orders him to go get the Charmander, since it's a known fact that if a Charmander's flame tail ever goes out, the Charmander will die. Damien refuses, and Ash is about to challenge him to a battle, when Nurse Joy steps in and tells them that the use of Pokémon in personal battles degrades their purpose. Brock says that she looks just like the all the other Nurse Joys and Ash adds that it's a Joy-full world. Brock then remembers the Charmander and decides that, since Damien won't get it, he will. Ash and Misty decide to come with him.
Back at the rock, Charmander's flame is almost out. Some Spearows start attacking it, but fortunately, Ash throws a rock and scares them away. Brock covered him with his poncho, while Ash made sure that his flame tail stayed lit. They get him to the Center just in time, and Nurse Joy is able to save it. It will take the rest of the night for it to fully recover. The next morning, however, Brock is sad to find that Charmander has left, most likely back to the rock to wait for Damien again. Ash is disappointed too, but he knows Charmander is loyal to his trainer, and accepts that. They all continue down the path.
Just ahead of them, Team Rocket has built a huge drill and use it to dig yet another hole. They cover it up and hide in the bushes nearby. Pikachu walks right over, but Ash and his friends fall in, leaving Pikachu unprotected. Team Rocket jumps out, wearing rubber suits. Pikachu tries to shock them, but to no avail. Then James fires a rubber balloon bazooka, and the bubble that comes out traps Pikachu inside. Team Rocket removes their suits, and Pikachu tries again to shock them, but the rubber in the balloon blocks the electricity again, so it's pretty futile. Jessie and James laugh at Ash and his friends in the hole.
They are about to leave with Pikachu, when Charmander shows up. He has remembered what Ash and his friends did for him, and he tells them to put Pikachu down. When they refuse, Charmander "chars" them with his Flame-thrower attack. They run off, dropping Pikachu. Ash and his friends climb out of the hole and thank Charmander, asking him if he wants to join them. Charmander is about to agree when Damien steps out from the bushes. He has been watching and is happy to see that Charmander is stronger. He credits it to himself and the fact that he left it behind to fend for itself, which toughened it up. He then adds how glad he is that he didn't have to go through the "boring" task of raising Charmander himself. He tells Charmander to come back to him, but he has lost Charmander's trust. When Charmander decides to stay with Ash, Damien is enraged, and threatens to attack it with his other Pokémon. Charmander then "chars" him, and he runs off.
Ash tells Brock to take Charmander, but Brock declines, saying that it would be happier with Ash. Ash tosses a Pokéball, Charmander jumps inside, and they all continue down the path towards their next adventure.