Dawn sat at her desk in her room at 1630 Revello Drive, staring down at her math homework. Trig functions. She was pretty sure she actually knew how to do them, but she couldn't force her mind to concentrate on it.
Buffy was out on patrol. She probably thought no one had noticed, but Dawn knew that each patrol had seemed to grow longer since she'd been back. It made her sad and a little angry to think of how little time she'd really spent with her sister since she'd been back. In all of the dreams where she'd imagined her sister's return, none of them had ever went like this: Buffy more quiet and distant than ever, and herself alone in her room staring out the window.
She wasn't technically alone. She knew Willow and Tara were downstairs, researching the latest big bad or doing something. She could go downstairs if she wanted. But she didn't particularly feel like moving from her spot, and she figured she would probably only be in the way anyway. That had to be why "the adults" never let her in on anything. Like when they brought Buffy back from the dead, she had been the last to know. Well, besides Giles and Spike. But that was different. Giles just would have disagreed and Spike...well, he was Spike. If she asked why they hadn't told her, she just knew what they would say. "You wouldn't have understood, Dawnie." "It was best if you didn't know, Dawnie." Maybe they thought she wouldn't have been mature enough to handle it. But after all that she had been through in the past year, maybe it was time they started to treat her like she was a little older than seven. She leaned back in her chair, the homework completely forgotten, and continued to stare out the window into the black night.
(Question: When exactly in S6/S3 is this set?)