Leaf trekked through the dark cavern, passing through the strange, maze-like structure and avoiding ample amounts of Pokémon. It would normally take a seasoned trainer hours or even days to get used to the layout of the place; however, Leaf had this place memorized. She remembered the trappings of her first few visits here... the strange dead-ends that always led to battles, the strong Pokémon lurking both on the land and in the water... none of that was going to be the case this time. She came prepared...
... and she knew that Blue knew that. That's why this was a perfect spot for them.
Leaf eventually made it to the deepest part of the cave. It was here where she encountered Mewtwo... and had failed to get it from Red all of those years ago. It was also here where she and her current Mewtwo spent together to meditate and share a bond... and it was here where she expected to find her counterpart.
Leaf took out a Poké Ball and tossed it.
Mewtwo knew why it was here, too. Sure, it was no longer bound by its previous master, Giovanni, but there wasn't a chance that Blue would just let it and Leaf stay partners... and it wasn't going to let her do that without a fight.
"I'm here, Blue." Leaf walked around, with Mewtwo following her. "There. Your people have attacked Goldenrod City and I chose to leave in favor for seeing you. Now it's just... me... and you."
"I'm serious, Blue. I know you made it here already. Don't try to act all quiet now. You said that you wanted to have closure? Well, let's have it."
"You know, it's really foolish for you to come all of the way in here and do exactly what I say. You really were too good for this world."
"... I'm not in a playing mood, Blue."
Blue stepped forward and made herself known. "Good, because I'm not in a betraying mood, either. It's good to finally see you face-to-face again, Leaf."
Blue turned to look at Mewtwo. "Oh, and you too, Mewtwo. Nice to see that you've grown accustomed to your new trainer, hm?"
Mewtwo rolled its eyes. Whatever, Blue.