When the children and the Gym Leaders, including Valerie, found the Ultimate Weapon in Geosenge Town, they tried to seal it. Grant had Mr. Mime attack the weapon to prevent its activation. Mr. Mime stood on solid air, using its own power, which was advised by Ramos to Valerie. However, Bryony sent Bisharp, who attacked Mr. Mime, causing it to lose the focus and drop itself and other Pokémon down, who could not fly nor levitate. After the Ultimate Weapon had been activated, Valerie had Mr. Mime create a barrier, along with Olympia's Slowking and Meowstic.
Valerie and Mr. Mime, along with other Gym Leaders, were fighting Team Flare forces, stationed at other cities.
None of Mr. Mime's moves are known.