Ash, Misty, and Brock are lost on their way to Vermilion again. They tried to take a shortcut, but it led nowhere. They stop for a break at a pond, and notice an Oddish taking a drink. Ash wants to catch it, but Misty is quicker on the draw and sends out her Starmie. She weakens the Oddish, and is about to catch it when a Bulbasaur leaps out of the bushes and whacks the ball away. He then Vine Whipped Starmie, must to the misfortune of Misty. Ash decides to catch the Bulbasaur and sends out Butterfree. He instructs Butterfree to use Sleep Powder, but Bulbasaur blows it right back at him and, as Ash tries to wake him up, Bulbasaur and Oddish run away.
Ash is upset that he didn't catch it, but they all continue on anyway. They soon come to a rickety looking rope bridge over a deep gorge. They carefully move across, but the ropes snap, and Brock falls down into the river below. Ash and Misty climb to the other side and start to look for Brock. It seems to be their unlucky day, though, when Misty falls into a pit, then later when they all get swept up in a net into a tree. They try to wriggle out, but to no avail. Bulbasaur appears again, laughs at them, and runs off. Ash starts to wonder what happened to Brock, imagining that he was swept out to the ocean and picked up by pirates.
His thoughts are broken by Brock himself, who cuts the rope and lets them down. He explains how he was being swept away in the river, when a girl saved him. He tells them that this girl, whose name is Melanie, lives in the forest, and runs a sort of health spa for abandoned Pokémon. She was the one who set all the traps in order to deter trainers who would try to catch the Pokémon. Brock says that he promised Melanie that they wouldn't catch any of the Pokémon there. Misty asks if he "sealed the promise with a kiss", only to be hit on the head by a blushing Brock.
Jessie, James, and Meowth appear on a cliff. They have heard of the village, and want to steal the Pokémon there. They follow the path Ash and his friends took, but fall into even more traps then Ash did. They all get really upset, since nobody ever falls into their traps.
Back at Melanie's, Ash and his friends are helping her care for the Pokémon. Misty notices the Oddish from earlier and apologizes. Oddish forgives it, but Bulbasaur, who appears on the scene, doesn't. It tackles her. Melanie explains that Bulbasaur had volunteered to guard the recovering Pokémon. It tackled Misty because it thought she was trying to take the Oddish. Melanie tries to convince him that Ash and his friends weren't trying to catch the Pokémon, but Bulbasaur doesn't believe her.
Team Rocket takes this moment to arrive with a flying stadium. A hose comes out, and they start to try to suck the Pokémon up. Unfortunately for them, Ash, Melanie, and the rest gather all the Pokémon into Melanie's cabin. This worries Jessie, but James points out that now all the Pokémon are in one place. Ash and his friends have just made Team Rocket's plan easier.
Bulbasaur comes back outside, and starts knocking the hose around with his Vine Whip. Ash comes out and sends out Pidgeotto. He has him use his Gust attack and the winds form a tornado, blowing Team Rocket and their stadium away. Melanie is very grateful and happy with how good a team Ash and Bulbasaur made. She insists that Ash take Bulbasaur to add to his party. Ash hesitates, saying that the Pokémon won't have anything to protect them. Melanie agrees, but says that Bulbasaur has a lot of growing to do, and that there's not enough room here. She goes on, explaining that the Pokémon she takes care of have grown too accustomed to this lifestyle and don't want to leave. She says that they need to go back into the wild where they belong, and possibly be caught by trainers like Ash. Bulbasaur agrees, but on one condition: Ash must beat him in a battle and actually capture him himself. Ash sends Pikachu, and he shocks Bulbasaur into a weakened state. Ash then captures him with ease.
Ash and Misty say goodbye to Melanie, but Brock offers to stay around and help out some more. Melanie declines, telling him to stick with his friends. Brock is disappointed, but leaves to go with Ash and Misty to Vermilion.