you're on the way to become Sinnoh's new champion! You've faced the Elite Four, and now you're going against the champion, you've had some encounters with this girl, Cynthia, an archaeologist, but now, you find out, she's actually the champion, you encounter her at there, she then starts talking

Cynthia: "Have you been keeping well? Thank you for Mountain Coronet. I'm truly grateful. Together, you and your Pokémon overcame all the challenges you've faced, no matter how difficult, it means you've triumphed over any personal weaknesses, too. The power you learned... I can feel it emanating from you. But that's enough talk, let's get to the reason why you're here, as the champion, I accept your challenge!"

she then gets on a battle position, ready to take out her Pokémon