Unfair-Weather Friends (Japanese: お天気研究所のポワルン！ The Weather Institute of Castform!) is the 43rd episode of Pokémon: Advanced Challenge.
The gang continues their journey to Fortree City. Suddenly, they are caught in a rain! They go at a nearest tree, but it has been struck by lightning. Suddenly, it begins to snow! A Castform appears before them, wanting them to follow it. They have no choice but to do it. The sun shines again, amazing everyone. Castorm changes into another form. Suddenly two scientists appear, while Brock goes with his flirting scheme. Max goes to pull him, but Brock seems to have his flirt frozen for some reason...
The scientists introduce - Bart and Millie. They offer them to go to the weather institute, to which they accept. Team Rocket is caught in the snow, annoyed to the fact "twerps dragged them here". Bart and Millie give them a quick tour of the institute. Bart is amazed Millie has been successful in so short time. Team Rocket see the institute and plan to steal the Castform. Team Rocket will improvise to get in, but suddenly, they see a plane arriving. Millie gives shows them the central computer, but Ash spots the plane.
Inside, Team Aqua's leader commands them to initiate the operation. Team Aqua go out and tie the scientists. The leader sends Crawdaunt to watch over them. Team Rocket spots the event and go to hide, but see other members of Team Aqua watching them close. Team Rocket recites their motto and in the end, they got tied up. They are put at the same place with the scientists. Team Rocket gets the air out of their lungs, so much their rings fall off, intimidating Team Aqua. However, one of them switches the machine on. The scientists drop to the ground, while Team Rocket is struck by lightning. The gang sees everything, so they suspect they are after the weather machine.
The leader demands the info about the Ancient Pokémon. Bart does not recall having any data about the Ancient Pokémon, except Kyogre and Groudon. The man can't get access to more data, requiring a special card. Bart places the card around Castform's neck and tells it to go to Millie. The Crawdaunt use BubbleBeam. Castform uses Weather Ball to knock out one of them, but is stricken by the other one's attack. The sun shines, so Castform changes its form and uses Weather Ball, hitting a Crawdaunt. Castform disappears into the vents of the building, so the leader orders to get the card back. Ash goes to stop them, but falls down. Millie mentions that the vents are connected to the room they are in, so Castform will arrive to them. However...
... however, Team Aqua appear. As they are about to go in the next room, Castform emerges from the vents. Castform goes to Millie, giving the card. Team Aqua is not stopped and will get that card. Brock, May, Max and Millie go, while Ash orders Pikachu to use Thunderbolt, electrocuting Team Aqua and their Crawdaunt. Team Aqua pass by, while the rest is hiding in the vents. Millie thinks they should hide the data instead. Max sees Team Aqua around the next corner, while they are convinced Castform is in the main computer room. Millie whispers something to Ditto - it transforms to Castform (with the card) and runs away, distracting Team Aqua. Fake Casform arrives to Ash and he takes it with him and going away.
Millie copies the data from the computer to a disc - info about Groudon and Kyogre - Pokémon that are believed to created the ground and water on Earth. The copying is complete, so Millie deletes the info from the main computer. They go out, but Ash bumps into Brock. Millie explains one of the Castform is a Ditto, so it shape-changes into its back shape. Team Aqua appear, so Ash sends Torkoal. Torkoal sneezes smoke, so the gang goes out of the building. They arrive to the place where Team Aqua has the prisoners. The leader demands the card for the prisoners. When a clear "no" has been said, a member codes the machine to produce lightening. It struck Team Rocket, blasting them off.
The leader's patience has gone to an end - she orders a member to code the computer. However, Millie gives them the card. The member searches for data, but finds nothing. Millie shows them the true card and jumps to an tower. She reveals herself - it is a man named Broadie of Team Magma! The Crawdaunt use BubbleBeam, while Ditto transforms and uses Bubble Beam as well, negating the attacks. May sends Combusken and uses Sky Uppercut, but is negated and hurt by Ditto's Crabhammer. The man uses a jet pack, disappearing. Team Aqua has nothing else but to go to their main base back.
Bart is stricken by the betrayal. A woman appears, introducing herself as Millie. Ash mistakes her for Broadie, but May corrects him - Brock flirts with her (unlike before where his flirting scheme was "cold"). Bart shows her the work she could do - transferring data from books to the computer. Millie is happy when she'll do that sort of work. Meanwhile, Team Rocket wanders in the snow, with Meowth being angry at the weather.
- Featured Pokémon: Weezing, Koffing, Muk, Cascoon.
- In the beginning of the episode, a classic Pokémon identification can be seen. In this case, it is an Abra.