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EP101 : Get Along, Little Pokémon
Original series
EP103 : Misty Meets Her Match
The Mystery Menace
Monster in the Sewers!?
First broadcast
Japan June 24, 1999
United States May 6, 2000
English themes
Opening Pokémon World
Japanese themes
Opening ライバル!
Ending タイプ・ワイルド
Animation Team Ota
Screenplay 武上純希 Junki Takegami
Storyboard 鈴木敏明 Toshiaki Suzuki
Assistant director 鈴木敏明 Toshiaki Suzuki
Animation director 志村泉 Izumi Shimura
Additional credits

The Mystery Menace (Japanese: ちかどうのかいぶつ!? Monster in the Sewers!?) is the 102nd episode of the Pokémon anime. It was first broadcast in Japan on June 24, 1999, and in the United States on May 6, 2000.

Spoiler warning: this article may contain major plot or ending details.


Ash and the group have finally made their way to the city of Trovitopolis, which should lead them right to Trovita Island and the next Orange League gym! Everything seems normal until the earth cracks right beneath their feet and they find themselves in the sewer underground, and not alone. There seems to be some sort of a monster living there that has been terrorizing the town. Will Ash, Misty and Tracey be able to find it, before it finds them?


Ash and his friends are walking through a mountainous desert region. Tired and hungry, Ash offers to eat if his companions are tired and hungry too. Tracey calls to Ash and Misty to see what he is seeing. They run up to Tracey, and they discover that they have come upon the city of Trovitopolis, the largest city on Mandarin Island South. Team Rocket spies on Ash and his friends, having just completed a large trap in which they plan to detonate underground dynamite to trap Pikachu. Meowth prepares to activate a trap button, but it turns out that the dynamite was beneath them the whole time. The trio falls into a deep sewer, but the explosion also collapses the ground beneath Ash and his friends, just as planned.

The group is woken up by Pikachu and Togepi, and they start to walk down the cave. As they do, the ringing of a bell is heard somewhere. Then, a Vine Whip comes from the water and taps on Ash's shoulder. Ash thinks that it was Pikachu and begs him to stop, though Pikachu isn't on Ash's shoulder, but on the ground in front of him. Another vine appears and the group sees this. Ash commands Pikachu to use Thunder Shock, but Misty states that if Pikachu uses an Electric attack, everyone will be shocked, so Ash sends out Bulbasaur. He tells it to use Razor Leaf, but the creature hits the leaves away before grabbing Bulbasaur and pulling it into the water. Ash attempts to jump in after it, but his friends hold him back. Tracey points out that he will be dragged down too, but Ash does not care and still attempts to jump in to save him. As they struggle for a while, Officer Jenny arrives from up above. Jenny explains that the sewers are very dangerous and throws a rope down to them. Ash refuses, wanting to find Bulbasaur, so his friends tie him up and Jenny hoists him to the surface.

Ash and his friends are thrown in jail, but Jenny releases them early. A man identified as the Mayor of Trovitopolis initially protests this, but is forced to acquiesce because it is the law. However, he orders the group not to say anything about the creature. When Ash tells the Mayor that he wants to get Bulbasaur back, the Mayor loses his temper and threatens to have them all arrested for endangering public safety. Jenny reveals to them that they are not the first people to have seen the creature. She reveals that the police force has had a number of reported encounters with a mysterious creature in the sewers, but no serious injuries were reported. She tells them that the Mayor says people will panic if word gets out about the creature, because they will never be able to capture it due to there being almost 500 miles of sewer underneath the city, and over 5,000 manholes.

The Mayor says that it is why they have taken drastic and immediate action to ensure the safety of everyone in the city. He also says that there is an election next week, and if word gets out that he is letting a monster roam the sewers, then he won't stand a chance. Nurse Joy comes in and tells him that she has heard what he intends to do about the sewer creature problem. The Mayor tells her that it is his business, and the group asks Nurse Joy about his plan. She tells them that instead of capturing the creature so it can be studied, the Mayor intends to send a SWAT team down to the sewers to destroy it. Ash and his friends respond by saying the Mayor's plan is cruel and that it could be a whole new species of Pokémon. The Mayor says that any talk of any such plan is pure speculation, and that there is no evidence. Jenny tells him that such a plan is illegal and the police force does not know anything about it. The Mayor loses his temper again, proclaiming that he is responsible for the city and he will do what he sees fit for the city.

At the Pokémon Center, the group speaks to Professor Oak about the new species. Ash asks Oak what they should do, and Oak says that there has to be some way of preventing the Mayor from destroying the creature. Nurse Joy does not think so, because the only thing the Mayor cares about is being reelected, and he is not going to let anything get in his way. The group see dozens of campaign posters all over building walls and park fences, as well as a statue of the Mayor. Ash decides to return to the sewers to search for Bulbasaur. Upon arrival, the group finds that the Mayor is briefing his SWAT team inside the sewer, but Ash knows how to find an entrance, since Nurse Joy gave them another entrance to the sewer on the other side of the city.

Meanwhile, Team Rocket is still trapped in the sewers. They hear the same bell-ringing sound, and the creature reappears and starts rubbing Meowth's chin. Meowth mistakenly thinks that Jessie or James rubbed him, but he finds that it wasn't them. The creature appears and Team Rocket flees in panic. After getting to a safe distance, they hear footsteps, and a flashlight is pointed at them. James sends out his Weezing and commands it to use Smokescreen; it engulfs the sewer with smoke. Team Rocket makes their getaway, screaming in fear. It turns out that Ash was holding the flashlight and his friends are there too. Ash asks if everyone is alright, then Misty notices that Togepi is missing. When they spot Togepi at the end of the path, Misty picks it up; but the creature suddenly appears, grabs Togepi, and pulls it and Misty underwater. Ash promptly sends out Muk, which he asked Professor Oak to send to him to aid them in their sewer exploration.

Meanwhile, Team Rocket comes across the Mayor's SWAT team, who mistakes them for the creature. The squad leader radios this to the Mayor, who commands them to attack immediately. The team opens fire at the trio with putty guns, forcing them to flee again. Elsewhere, Ash, Tracey, and Muk come to a dead end. Muk points out that they have to go into the underwater tunnel to find Misty, Togepi, and Bulbasaur. Ash and Tracey jump in, swim down the tunnel, and eventually reach the end, where the creature appears and attacks them.

Meanwhile, the SWAT team emerges from the sewer and reports to the Mayor that beyond Team Rocket, they couldn't find a creature that matched the original description. The squad leader comes to the conclusion that the sewer could be infested with multiple unidentified creatures. The Mayor grows increasingly paranoid and orders that every manhole to the sewer be sealed off.

Elsewhere, the group wakes up and sees an opening into the city. They also see Misty and Bulbasaur. Tracey finds the creature, who actually is a giant Bulbasaur that has been living down there for a long time and was actually using Vine Whip. Ash notices that it has the Mayor's symbol on its collar.

Back at the Mayor's office in City Hall, Nurse Joy explains to him that Ash and his friends are in the sewers and they will be trapped there if all of the exits are sealed. The Mayor assures Joy that he will remove all of the concrete as soon as the election is over. Later, while the Mayor is taking a bath, an earthquake starts, and water forcefully erupts from the floor right under the Mayor's bathtub. The bathroom, the City Hall, and the entire town are flooded. The group emerges with the giant Bulbasaur, and Ash asks if it looked familiar to the Mayor. He sees his trademark "M" initial on Bulbasaur's collar and explains that he abandoned his Bulbasaur in the sewer as a child because it wouldn't evolve. Upon learning this, the Mayor's Bulbasaur grabs him with Vine Whip. Ash's friends accuse the Mayor of abandoning it despite its love for him, whilst many townspeople see the Mayor half-naked, leaving him embarrassed. Misty orders him to apologize to his Pokémon for what he did, but he refuses.

The SWAT team arrives, and the Mayor orders them to open fire on Bulbasaur. However, Ash steps in and commands Pikachu and Bulbasaur to use Thunderbolt and Vine Whip, respectively, on them; this sends the SWAT team flying off. The Mayor says that he will offer a truce with his Bulbasaur, but Bulbasaur spins him around and throws him into his statue, toppling it and his chances in the election next week. Later, Officer Jenny thanks Ash and his friends for their help, and Nurse Joy says that she will take care of the giant Bulbasaur at the Pokémon Center. When Ash asks where Trovita Island is, Joy points it out, but it is almost far away. Officer Jenny, however, agrees to take them to a ferry that heads there.

Meanwhile, Team Rocket finds an exit from the sewer system, but it has bars on it and they realize they are trapped. Jessie sneezes and breaks the metal bars, setting them free.

Major events

For a list of all major events in the anime, please see the history page.


Pokémon debuts



Dare da?


Who's That Pokémon?

Who's That Pokémon?: Zapdos (US and international), Bulbasaur (Japan)


Pikachu surfing


Tracey's backpack error
  • During the beginning of the episode, Togepi's voice is cut off a second or two before Tracey starts to talk.
  • After Ash, Misty, and Pikachu pull Tracey out of the rock, he thanks them and realizes that he is sitting on top of Ash. However, when Tracey was freed from the rock, the scene shows Ash falling away from Tracey and he falls on to the ground rather than Ash.
  • The straps on Tracey's backpack are orange instead of black when the "monster" first attacks.
  • The shoes on the mayor's statue are red instead of brown.
  • When Misty finds Togepi, the blue triangle symbol on its shell disappears.
  • When Tracey presents the "monster" to Ash and Misty, a back shot of the Bulbasaur shows it without its blue collar. Seconds later, it is seen wearing it in a full shot.
  • When Ash and Tracey are with Muk, they jump into the water without recalling Muk. Yet when Ash wakes up, Muk is with them.
  • After the mayor crashes into his statue, he inexplicably has a beard.

Dub edits

In other languages

EP101 : Get Along, Little Pokémon
Original series
EP103 : Misty Meets Her Match
Project Anime logo.png This episode article is part of Project Anime, a Bulbapedia project that covers all aspects of the Pokémon anime.