Ash and co. continues their walk through the desert. Ash wants to take a lunch break. Tracey sees something, and he signals Ash and Misty over. They see the big city right ahead of them. Team Rocket has arrived at the city too. Meowth plans to use dynamite to capture Pikachu. He says that they are prepared. Jessie and James starts the motto, but Meowth knocks them down. Meowth tells his friends that they should make it a sneak attack. James takes out a remote and pushes the button. Nothing happens. Suddenly, they realize that they are standing on the trap, and they fall down into the hole. Misty hears a scream. Suddenly, the group that Ash and co. are standing on collapses.

Ash and co. find themselves in a tunnel. Misty spots a tunnel, and they all follow it. At the end is a bright light. Ash and co. are now near a sewer. They search for a place to escape. Ash looks around. He hears a bell ring, but Misty and Tracey do not hear the sound. A green vine taps Ash on the shoulder. Ash thinks that it is Pikachu. When Ash turns around, nothing is there. He sees in Pikachu infront of him. Suddenly, the vine comes out again. Misty and Tracey sees it, and Misty tells Ash to get away from the "monster." Ash tells Pikachu to use Thundershock, but Misty reminds him that they will get shocked too. Ash sends out Bulbasaur. Bulbasaur uses Razor Leaf, but the vine blocks them off. Then the vine reaches down and grabs Bulbasaur, pulling it underwater. Ash wants to dive in the water, but Tracey tells him that he can't. Officer Jenny looks down a hole. She lowers a rope to help Ash and co. up. Ash struggles exclaiming that he wants his Bulbasaur back.

At the police station, Ash and co. are put into jail. Ash is pounding the door because he wants to get his Bulbasaur back. Officer Jenny reports to them that they are free to go. The mayor comes in the room. He wants to have Ash and co. locked up in prison. Officer Jenny tells him that she can't do that because they didn't do anything wrong. The mayor agrees, and he tells them to not say anything about the creature that took Bulbasaur. Officer Jenny tells Ash and co. the story about the creature. The mayor wants this to be kept a secret because there is an election next week, and he wants to win it. Nurse Joy comes barging in the room. She does not like the mayor's plan. Nurse Joy tells Ash and co. that the mayor plans on destroying the creature instead of capturing and studying it. Officer Jenny tells the mayor that his plan is illegal. This gets the mayor mad.

When they call Professor Oak, he thinks that it might be a new kind of Pokémon. Nurse Joy adds in that the mayor only cares about being re-elected. Outside, there are posters, pictures, and even a statue of the mayor. Meanwhile, the mayor is talking to a SWAT team. He tells the team to exterminate the creature. Ash tells himself that they have to get in the sewer, or Bulbasaur and the creature will be finished.

Nurse Joy leads them to an cave opening. Ash begins to climb, but he slides off.

Team Rocket has also fallen into the sewer. They have been trying to find a way out all day. Meowth hears a bell ring, and the same green vine begins to scratch Meowth across the chin. Meowth likes the feel of it. Suddenly, Team Rocket sees the green vine, and they quickly run away from it. When the monster is gone, Team Rocket stops for a break. A bright light flashes from across the sewer. Scared, James sends out Weezing which uses Smokescreen. Then Team Rocket runs away. The bright light came from Ash and co. Misty finds Togepi missing from her arms. She sees Togepi on the ledge, and she quickly grabs it. Behind her is the creature, and it grabs Togepi. Misty holds onto Togepi tight. She is pulled underwater as well. Ash sends out his Muk. Muk tramples Ash to the ground.

Team Rocket is scared and exhausted from running. Meowth takes a stand saying that they have to do the scaring now. They dress up in scary outfits, and they run right into the SWAT team. The team fires their guns at Team Rocket, just as Team Rocket runs away. Ash and Tracey comes to a dead end. Muk points to a tunnel that's hidden underwater. Ash and Tracey dives into the water, and they swim in the tunnel. The tunnel ends and they head up to the surface. The SWAT team reports to the mayor that they saw three other creatures (Team Rocket) in the sewer. The mayor orders them to seal all of the holes that lead into the sewer. The holes are sealed with cement, trapping Ash and co. inside.

When Ash wakes up, he sees Bulbasaur. He hugs Bulbasaur and is glad that it is okay. Tracey points to another Bulbasaur, and he says that this Bulbasaur was the creature who was using Vine Whip. There is a collar on the Bulbasaur, so it isn't a wild one. Ash goes up to pet the Bulbasaur. He sees something very familiar on the collar. Meanwhile, Nurse Joy is trying to get the mayor to not close up the sewer entrances because Ash and co. are trapped inside. The mayor tells her that he will reopen the entrances once the election is over.

The mayor is busy taking a bath. Suddenly, he hears a loud noise. A bunch of water bursts out from the bottom of the tub, and it fills up the hallways. When the mayor lands on the ground, Ash and co. approaches him. Ash asks the mayor if the Bulbasaur belongs to him. The mayor sees the collar with his initial on it. He recalls back a time when he let his Bulbasaur go because it couldn't evolve. The mayor's Bulbasaur picks him up with its vines. The mayor is afraid that he will lose the election. The SWAT team arrives at the scene. The mayor tells the team to get rid of the Bulbasaur. Pikachu uses Thunderbolt on the SWAT team. Then Ash's Bulbasaur uses Vine Whip to send them away. The mayor's Bulbasaur swings the mayor around, and it lets the mayor fly in the air. The mayor lands right into his statue.

Officer Jenny and Nurse Joy thanks Ash and co. for their work. Nurse Joy agrees to take care of the Bulbasaur. Then she points to Trovita Island, the place where the next Orange League gym is held. Ash and co. are taken to a pier where they can sail to the island. Meanwhile, Team Rocket sees the sunshine. Unfortuantely for them, they are trapped in the sewer. Jessie sneezes and the bars break. Team Rocket is free.

English Official Summary

In Trovitopolis City, Ash and friends hear stories about some kind of monster that's been scaring everyone—and when the ground cracks open and dumps them in the sewer, it seems they might meet this monster face to face!

Italian Official Summary

Ash e amici giungono finalmente a Trovitopoli, dove dietro l'apparente normalità si nasconde un segreto... E quando precipitano in una galleria sotterranea, potrebbero finire per affrontarlo in prima persona!

Portuguese Official Summary

Na Cidade Trovitopolis, Ash e os amigos ouvem histórias sobre uma espécie de monstro que tem assustado toda a gente, e quando o chão se abre e os atira para o esgoto, parece que poderão conhecer este monstro cara a cara!

Spanish Latin America Official Summary

Ash y el grupo han conseguido finalmente llegar a la ciudad de Trobitópolis, que debería llevarles directamente a Isla Trobita y ¡al siguiente gimnasio de la Liga Naranja!

Spanish Official Summary

Ash y el grupo han conseguido finalmente llegar a la ciudad de Trobitópolis, que debería llevarles directamente a Isla Trobita y ¡al siguiente gimnasio de la Liga Naranja!

English Great Britian Official Summary

In Trovitopolis City, Ash and friends hear stories about some kind of monster that's been scaring everyone—and when the ground cracks open and dumps them in the sewer, it seems they might meet this monster face to face!

Dutch Official Summary

In Trovitopolis City horen Ash en zijn vrienden verhalen over een monster dat iedereen schrik aanjaagt. Dan barst de grond open en komen ze in het riool terecht. Ze staan oog in oog met het monster!

French Official Summary

Sacha et ses amis finissent par atteindre la ville de Tartofoupolis, qui doit les mener directement à l'Île Tartofou et à la prochaine Arène de la Ligue Orange !

German Official Summary

Ash und seine Freunde sind endlich in Trovitopolis angekommen, von wo sie direkt nach Trovita Island und der nächsten Arena der Orange-Liga gelangen können.

Danish Official Summary

I Trovitopolis City hører Ash og hans venner om et monster af en art, som skræmmer alt og alle – og da jorden åbner sig under dem, og de falder ned i kloaksystemet, frygter de at møde monsteret ansigt til ansigt!