Set between the point when Sora releases Kairi's heart and when he returns as a heartless.
He was falling. Falling and falling and falling. He didn't want to fall anymore. The lack of substance and destination was beginning to terrify him. He couldn't tell if his eyes were open or closed, or if he even had eyes at all. Everything was black and everything was nothing. He shivered and choked on a sob. He could feel the actions in a strange, disconnected way.
"Sora?"
He jerked, flailing around and straining his possibly non existent eyes for the source of the sound. Only the voice wasn't really a sound at all, and yet he recognized it as a sound. . .
"No, Sora, you shouldn't be here, what are you doing here?"
Suddenly the falling stopped. He felt a hand grasp his arm and then a pair of arms wrap around him. He felt it, even though he wasn't sure any of those body parts existed. "Ri. . .ku?" Wherever his voice came from, it sounded horse and strained and his throat suddenly felt like he'd been screaming for days on end. Maybe it was because he was forcing his throat to exist in this non existence. "Riku, where are you?"
"I'm right here, dummy." Riku's voice responded. The arms around him tightened.
"But . . I can't see you."
". . . I know. Sora, you shouldn't be here. You have to go back."
"You don't belong here either, Riku!"
"Sh, he's moving."
"Who's moving?"
"No. . . I have to. . ."
The arms disappeared from around him and he instantly began to panic. "Riku? Riku?! Riku!"
It was hard to tell how long it was before Riku's voice returned. When it did it sounded weak and exhausted. "You have to go back, Sora. Kairi needs you."
"Kairi!" Sora exclaimed as he felt the arms wrap around him again. "Did it work? Is she awake?"
"Yeah, but she's in danger. You have to go back."
"Come with me!" Sora said, twisting to try and look where Riku's face should be. He sensed Riku shake his head.
"I can't. I'm connected to Ansem now."
"No, Riku. . . I'm not leaving without you."
Riku smirked and pulled him closer "You probably won't remember this at all," he whispered into what should have been Sora's ear. "But. . . I'm sorry." And then he pushed. With all his strength and all his power he sent Sora flying back to the world of light. He's have nothing to return to except a body of a heartless. But Kairi had powers of her own, and she was sure to save her knight in shining armor. Because that's how it was. Kairi was the pure hearted princess and Sora was her White Knight and Riku. . . Riku was a mistake. He knew that now, he excepted it. Every choice he had ever made had been wrong. His attachment to Kairi, his love for Sora, his desperate need to stretch his wings and just discover, all of it was just wrong. He deserved to be here. But that didn't mean he wasn't scared. It didn't mean he was desperately wishing Sora was still there in his arms.