The anime’s ending leaves a great deal up in the air; this story takes up some of those loose threads. Picks up immediately after the end and throws everyone a little further into the future.
“Takuto is with him,” Wako said firmly, eyes fixed on the sky. “They’ll be all right.” Takuto’s look had promised her that, in that long, silent moment of fierce understanding they’d shared before she’d agreed to break the southern seal. And she was going to hold them both to that promise, if she had to regenerate Wauna and go up there herself to make sure of it!