Showdown at Dark City (たいけつ！ポケモンジム！ Showdown! Pokémon Gym) is the 42nd episode of Pokémon: Indigo League.
Coming into Dark City, the heroes hear a battle between two rival forces: Yas and Kaz Gyms, who want to be promoted as the official Gym from the Pokémon League. The battles get more and more violent, so Ash, Misty and Brock decide to stop both forces before they destroy the town.
Ash, Misty, and Brock arrives in Dark City. They are surprised when they see a parent taking her child away from the area because of Pokémon trainers. Ash and his friends wonder what's going on, and Pikachu gets hit on the head with a rock thrown from the roof of a building. Ash tells Pikachu to use Thunderbolt in the direction the rock was thrown from. The Thunderbolt hits three kids. Ash and his friends apologize to the three kids, but they tell them to get out of town. The kids are about to throw more rocks at them when a restaurant owner stops them. He then invites Ash and his friends to his restaurant.
At the restaurant, while eating (here, Pikachu eats Ketchup from a bottle and loves it), the owner tells Ash and his friends and a mysterious patron who overhears that Dark City has two rival official Gyms, the Yas Gym and the Kaz Gym. Both Gyms want to become official and the league inspector is supposed to come any minute. Both Gyms are recruiting trainers to eliminate the other gym. At that moment, fighting between the gyms breaks out outside the restaurant. Ash and his friends notice that the fighting is not like a Pokémon battle, but like a gang war. The Kaz Gym's Electabuzz and the Yas Gym's Scyther are sending out new trainers to fight every minute.
Team Rocket, who have been hired by the Kaz Gym as elite bodyguards, invade the restaurant and demand food. The owner refuses because the Kaz Gym has a large tab. Ash and Misty have Pikachu and Starmie protect the restaurant owner and try to make Team Rocket leave. Brock has Vulpix force Team Rocket to leave by using Flamethrower. Vulpix's attacks have been noticed by a Yas Gym recruiter, who tries to get Ash and his friends to join the Yas Gym. To protect their identities, Ash introduces himself as Tom Ato, Misty as Ann Chovy, and Brock as Caesar Salad. After Brock agrees for Ash and Misty to join the Yas Gym (since the recruiter was a pretty girl) The Yas Gym recruiter takes them to the Yas Gym.
At the Gym, the Yas Gym leader is introduced to Ash and his friends. The Yas Leader shows how strong he is by having his Scyther suddenly attack Pikachu. Scyther's Cut attack is blocked by the ketchup bottle that Pikachu is still holding. The ketchup squirts Scyther in the eye and Scyther accidentally attacks the Yas Gym Leader. The Yas Gym Leader is surprised, recalls Scyther, and asks Ash to join him. Ash asks him why he wants the gym to become official and he says he wants to earn more money quicker. Ash doesn't like this, so he refuses the Yas Gym Leader's offer. The Yas Gym Leader is mad and he tells his followers to beat up Ash, which they do by sending out a Hitmonchan, a Hitmonlee, a Mankey, and a Machoke. to beat him up.
Ash and his friends quickly leave the gym. Back at the restaurant, Ash checks the Pokédex and it says that Scyther and Electabuzz both hate the color red and will start fighting if they see it. Ash and his friends make a plan to defeat the Yas and Kaz gyms at once using this knowledge.
Soon, fighting on the streets breaks out again. Scyther, using Swords Dance and Cut destroys Kaz buildings easily and Electabuzz does the same to Yas forces by using ThunderPunch. Ash tells Misty, Brock, the restaurant owner, and the kids from earlier to dump barrels of ketchup on the trainers from the rooftops. Scyther and Electabuzz start attacking their own trainers. Ash ends the fighting by having Bulbasaur dump ketchup on Electabuzz and Scyther. The two start attacking each other and they knock themselves out.
Ash asks the Yas and Kaz leaders if they will stop fighting. They do, but they team up to fight Ash. Ash has Pikachu use Thunder on them and both leaders are stunned. The mysterious patron from the restaurant appears and says that she's from the Pokémon League Inspection Agency before throwing a Poké Ball, which releases a Chansey. Upon seeing this, Brock instantly realizes who the patron must be, and the patron agrees right before taking off the disguise they're wearing. Much to the surprise (as well as dismay) of Kaz and Yas, the patron happens to be none other than Nurse Joy. She says that neither gym deserves to be official because using Pokémon for street fighting won't be tolerated. Nurse Joy says she will give them a second chance and tells them that Ash would be a good teacher on how to be good trainers and unite the Yas and Kaz gyms. Ash isn't sure what to do, but he convinces the leaders to pay for all of the damage they caused.
When Ash and his friends leave Dark City, they see the kids again. They have become fans of Pikachu and have decided to become trainers themselves.
Meanwhile, Team Rocket, covered in ketchup, are run out of town by Scyther and Electabuzz.
- The town style makes it look like an old Western era town.
- The "Who's that Pokémon?" in this episode is Scyther.
- Pikachu's shown to have a strong fondness for ketchup in this episode.
- In one of the Ketchup scenes, Pikachu's red cheeks are missing.
- There is an error on the location type name. The location is called Dark City. However, the Narrator says it's a town.
- "We don't care who you are! If you have your Pokémon, you get out of our town now!" - Child
- "Why? What's wrong with Pokémon?" - Ash
- "Stop it, boys!" - Restaurant owner
- "I apologize. These children won't cause you any trouble. Come to my restaurant and I'll explain everything." - Restaurant owner
- "Well, okay." - Ash
- "I'm... Ketchup." - Ash
- "Ketchup?" - Yas Gym Recruiter
- "Uh, no. My name is Tom Ato." - Ash
- "Well, my name is Ann Chovie." - Misty
- "And my name is Caesar Salad." - Brock
- "Brock just can't say "No" to a pretty girl." - Misty