They are a pair of rich young sisters who are traveling the world in the massive "Leviathan Two", a luxury blimp. They dress in fur coats and each have a Kecleon. Brock helped their Kecleon recover from motion sickness.
Reddy and Greeny
Madison and Alexa each own a Kecleon, Madison's being Reddy (Japanese: アズキちゃんAzuki-chan) and Alexa's being Greeny (Japanese: ミドリちゃんMidori-chan), respectively. The two Kecleon like to steal things to cause people to play hide and seek with them. The Kecleon had motion sickness when Ash and his friends saw them. Shortly afterward, Brock gave them some medicine and home-made Pokémon food, and they became well again.
When playing in their room, Greeny spotted Meowth with Alexa's jewelry box, and it quickly used its tongue to snatch it from him. Later the Kecleon went missing and the group tried to find them; Team Rocket were pursuing the Kecleon, which were running all around the blimp. The Kecleon were able to escape on several occasions, and in the end, Team Rocket were sent blasting off. Madison and Alexa were happily reunited with their troublesome Pokémon, and returned a stolen gentleman's first aid kit, which the Kecleon had also stolen.