The episode starts with Ash and Pikachu looking over the sea, imagining the upcoming battle in the Orange League. They do a little gazing at the four badges pinned to the inside of Ash's jacket. A big wave splashes over them both, stunning them back into reality, so they both start walking back. On the way, Ash and Pikachu see Tracey making some sketches of a huge Vileplume. Ash calls out and runs towards the Vileplume, but he trips on a tree root, and smashes into Tracey. They both are all tangled up when they fall into the Vileplume's center. The shocked Vileplume suddenly uses Stun Spore while both guys are stuck in its center, so they get the full blast of it.
Misty and Togepi are walking along another path when Pikachu runs out from under a bush, calling out frantically. From Pikachu's frantic cries for help, Misty realizes that something's wrong.
Next scene, Ash and Tracey are laying down on mats on the floor of a small hut, covered with blankets. Both are shuddering from the Stun Spore encounter. Misty's dabbing wet cloths over both their heads, when Tracey (without his headband on, I might add) calls out to Misty, and tells her to get Ash's Pokédex out of his jacket. She goes and retrieves the Dex, and Tracey tells her to look up Vileplume antidotes. The Dex says that a special weed called Sangora Weed, which is found at the bottom of lakes, can help cure Stun Spore if boiled in water. Also, the weed is found wherever Poliwags are found. So leaving Pikachu behind to help Ash and Tracey, Misty takes off towards a nearby lake.
Meowth and James are in a different hut with Jessie lying on the ground. She too is blanketed and shaking. In a flashback, it depicts Jessie running in a flowery field. She leaps into the air, but lands headfirst into a Vileplume, who then uses Stun Spore. End of flashback. Meowth and James are wondering what to do, when James remembers that once when he was little, he got Stun Spored, and he was cured with Sangora Weed tea, which was the weed boiled in water. So leaving Jessie in the hut, they both take off.
Misty is searching amongst some lake weeds, but finding no Sangora weed. Frustrated, she sits down and takes a break. But just then, a Poliwag pops out of the lake and leaps on a rock, a sprig of Sangora Weed on its tail. Misty is delightfully surprised, and is about to ask the Poliwag to help, when James and Meowth appear, and try to capture Poliwag. It hides behind Misty as James and Meowth approach. They say they are there for Poliwag, because it is needed to find some Sangora Weed to help Jessie. A battle commences, but is ended quickly as James and Meowth fall down the side of a cliff. Finally able to talk, Misty asks Poliwag to locate some Sangora Weed, and Poliwag leads her down to the lake bottom, where Sangora Weed grows plentifully. Harvesting an armful, Misty and Togepi start running back towards the hut where they had left Ash and Tracey. James and Meowth are trying to find a way to get some Sangora Weed from Misty, and they get the idea to try and temp Misty into a trap with things such as cosmetics, dresses, and food, but nothing works, because Misty's resolve is to help her friends. Another encounter between the Rockets and Misty occurs again, and Poliwag, who has been following Misty all this time, Water Guns them away. Misty leaves a heap of weed in the path where she knows that James and Meowth will find it, and runs for the hut.
Meowth and James stumbles onto the path where Misty just was, and find the Sangora Weed in the path. They start saying some praise about her, that the two other twerps are lucky to have that twerp care for them so much. They take the weed and run back to their hut. Misty boils the weed, and gives the tea to Ash and Tracey, who both say thanks. The tea seems to work, because both guys are able to move around. Back in the other hut, Jessie receives the tea, and is also better. She realizes that if two of the twerps are ill, it would make them easy pickings, and drags the reluctant James and Meowth towards where Misty, Tracey, and Ash are. Meanwhile the two sick boys are finally going outside for some fresh air, when Jessie appears suddenly and says the speech. Everyone's on alert, but James and Meowth are hiding behind a boulder, too ashamed to even appear, while Jessie's shouting at them to appear and help her attack. James and Meowth pick her up and run off, with Meowth saying 'Thank you, oops I mean Team Rocket's blasting off again!'
Poliwag rubs up against Misty, even though she said that they all have to leave the island, but since Poliwag is so insistent on coming along, Misty captures it, and it becomes another one of her Pokémon.