Ash, Misty and Brock are on course for Goldenrod City. Their map says that they can take the Onix Tunnel through a mountain to make the journey a bit shorter. Many Onix are said to live in this cave, but Ash knows that Onix are weak against water types. Then he remembers that he no longer has Squirtle, but Misty reassures him that she can use her water Pokemon. Brock suggests that they go through the tunnel in the morning because it's getting dark.
Unbeknownst to them, they are being followed by both Jigglypuff and Snubbull. In the morning, Team Rocket comes to the tunnel. Meowth complains about going in, but James says it's the shortest route to the next town. No sooner to they enter the tunnel they meet a bunch of Onix. James has Victreebel use its Razor Leaf but it has no effect on them. The Onix start to bash the sides of the tunnel, causing rocks to fall down. Angry, Jessie sends Arbok out but it gets caught by one of the Onix. So she throws Meowth, but his Fury Swipes doesn't work either. The Onix continue to cause rocks to tumble down, so Team Rocket runs away.
They lament about not having any water Pokemon. Wobbuffet comes out and Jessie has to put it back. Jessie remembers that Misty has water Pokemon, so they'll steal hers. Ash and Misty are washing up while Brock does exercises with his Pineco, which explodes in his face when he picks it up. Pikachu sees Snubbull walk by and alerts the others, they recognize it as the one from the rich lady's house. What's it doing so far from home? The Snubbull runs off, and they follow it.
They turn a corner and encounter Jigglypuff, who hops up onto a tree stump and sings. Ash mutters that they're taking their afternoon nap a little early, and they all fall asleep. Team Rocket, who has been sneaking through the bushes nearby, also hears Jigglypuff's song and dozes off. Snubbull finally sees Meowth and runs forward, but flops onto the ground inches from his tail.
Snubbull is the first to wake up, and when she sees her reflection in a puddle she gets mad. When she sees Jigglypuff angrily scribbling on a sleeping Pidgey, she grabs its marker/microphone and runs away.
Our three friends are continuing on their way. Misty comments that Ash's mother would be happy to hear about them washing up twice in one day. Jigglypuff shows up again and they're afraid that it will sing, but Brock notices something different about it: it doesn't have its microphone any more. They decide to help Jigglypuff find it.
Team Rocket grumbles about Jigglypuff ruining their plan. Jessie has another plan to dig a pitfall trap. James is skeptical but she produces her secret weapon, a combination spade and pogo stick. They start to dig. Snubbull finds them and chomps Meowth's tail. Jessie picks her up and makes her let go, hoping Snubbull's teeth didn't get damaged. She thinks Snubbull has been following them because she's in love with Meowth (much to Meowth's dismay). James wants to give Snubbull to the boss, but Jessie wants to keep it. Jessie is jealous, everyone thinks Misty is sweet because she goes around hugging her Togepi, so if Jessie keeps Snubbull she will become as popular.
Meowth gets angry and says he doesn't want his tail to get chewed off, but Jessie isn't giving him any choice. (Wobbuffet comes out again, just to be annoying.) Meowth says either Snubbull goes or he goes, but Jessie and James welcome Snubbull to the team and Meowth is devastated and wanders away.
Back on the road, Ash sees a basket of fruit and wants to check it out but the others stop him, saying this looks too familiar. However Jigglypuff runs forward and falls into a hole. Ash has Bulbasaur rescue it, but Jigglypuff falls into a second hole, then a third. After the third rescue, Jigglypuff gets angry and runs away.
In the bushes, J&J are angry that Jigglypuff ruined their plan. James wonders where Meowth is, whereupon Snubbull squirms out of Jessie's arms and goes to search for Meowth. J&J have little choice but to follow. A dejected Meowth is wandering along the road. He hopes that J&J will come to look for him, especially since they need him to say "Meowth that's right!" in the team's motto. He looks back but nobody is there, so he keeps walking.
Ash and friends are still looking for the microphone in the woods but they agree they'll never find it at this rate. Jigglypuff is sad and walks up the road. Meowth has stopped at the entrance to Onix Tunnel, unwilling to go through. Jigglypuff sits down beside him and tells him about its lost microphone. Meowth complains that nobody seems to care about Pokemon's feelings any more. Still, they have to follow their dreams. Jigglypuff tells him about its dream to have an audience listen to its song all the way through, and Meowth realizes that Jigglypuff looks like the full moon that he likes. He suggests that they form their own team, the Dream Team, and they won't stop until their dreams come true!
In the middle of a sentence, something bites Meowth and he panics. It's Snubbull! J&J arrive and Meowth asks them if they had been looking for him but they tell him they were looking for Snubbull. Jigglypuff sees that Snubbull has its microphone and tries to grab it, but Snubbull won't let go so they start to slap each other around. Pikachu sees this and runs to get Ash.
J&J tell Meowth to help Snubbull but Meowth has been hoping that Jigglypuff will slap Snubbull silly. He reluctantly tries to break up the fight but ends up getting drawn into it himself. Ash and company arrive and stop the fighting. Team Rocket threaten to steal Misty's water Pokemon and say their motto; Meowth prepares to jump in and say his line but gets interrupted by Wobbuffet! Jessie says that has a nice ring to it, and Meowth gets upset.
Now Jessie releases Arbok. Misty gets a Pokeball but Psyduck comes out by itself and she has to recall it before releasing Poliwag, which makes short work of Arbok with its Water Gun. James releases Victreebel but it tries to chomp him. Ash gets out Chikorita which easily takes care of Victreebel. Jessie throws Wobbuffet into the action and it counters Chikorita's attacks, but Poliwag uses a full power Water Gun to push Team Rocket back. Pikachu finishes the job with a Thunderbolt, sending them blasting off.
Snubbull tosses the microphone aside and runs after Team Rocket. Jigglypuff is happy to have it back and immediately sings. Ash's last comment before falling asleep for the second time today is that this is getting tiring. After scribbling on their faces, Jigglypuff heads into the tunnel and puts all the Onix to sleep.
Later, the three friends walk through the tunnel to discover all the Onix are sleeping and have been scribbled all over. They consider themselves lucky and pass safely through the tunnel. Team Rocket go through the tunnel themselves, but Jessie trips over a rock and falls. The noise wakes up all the Onix! They're trapped here for a while...