Marble met Ash and his friends in front of an old mansion. Suddenly, her LuxrayattackedAsh's Pikachu. After the battle was over, Marble called the security guards over because she thought they were a group of thieves, dubbed The Bandit Beauties Three (Japanese: The Three Beauties), that were trying to steal the Old Charm.
Marble explained that she—being the best Officer Jenny student—was called to the mansion by Matthew and assigned to protect the Old Charm from being stolen. Then, Marble revealed that Luxray—who she has raised since it was a Luxio—had a problem in learning Charge Beam. Towards the end of the episode, Marble's Luxray finally learned Charge Beam; with Pikachu, it attacked Team Rocket and blasted them off.
Marble is very quick to jump to conclusions, and never admits when she is wrong. She often says, "I was just about to say the same thing!" Marble is very vain and not at all humble, such as when she said, "I may never be sure who spilled the beans, but now that they've all been spilled, I'm the super-duper ace detective, Marble!" Also, Marble is usually the one to have "spilled the beans".
This is a listing of Marble's known Pokémon:
Luxio → Luxray
Marble's Luxray was having serious problems when Marble met the gang. It had recently evolved from Luxio and was unable to use Electric-type moves, making it a liability to Officer Jenny. As a result, Luxray developed a serious attitude problem, which not only caused it to constantly disobey Marble, but also caused it to fight other Electric-type Pokémon, like it did with Pikachu.
After Team Rocket stole the Old Charm from under Marble's nose, Luxray and Pikachu were trapped below the mansion it was guarding, in a maze filled with traps. After being saved by Pikachu from a trap, Luxray's attitude softened and it became friends with Pikachu. Luxray's enhanced eyesight allowed it so see other booby traps and it was able to save Pikachu from one later. After reestablishing its bond with Marble and regaining its Electric-type moves, it helped defeat Team Rocket and recover the Old Charm.
Marble has the same attitude as the Officer Jenny in Johto, who appeared in An EGG-sighting Adventure!. Like Marble, that Officer Jenny also has the habit of jumping to conclusions and saying the phrase, "I was just about to say the same thing!"