Bella is about to turn thirteen! This is exciting.
Sherlock is curled up next to Tony, not doing much of anything at all.
She looks at her glowy person, which turns around and regards them.
The glowy person doesn't have discernible eyes, but it crouches by the picnic blanket, and reaches out and puts its hand on Sherlock's forehead.
Then he uncurls. It feels like sunlight. Like getting a hug from sunlight.
Bella's breathing normalizes, meanwhile, and she is watching what her Patronus does.
Eventually, it dissipates.
Bella sits down, hard, on the picnic blanket.
"With a - super-Patronus. I wasn't sure if it would work but it worked."
"What did you actually do, is what I'm trying to get at here," says Tony.
"I sort of - you know how I got mist when I thought about the right books - I just thought about - I'm not sure how to put it in words."
"...Oookay," says Tony. "Bella has Special Patronus. Got it."
"I'm pretty sure I could do it again, now that I know I can."
"...You're gonna want to go around slaughtering Dementors now, aren't you."
Hugs. "I will need to think of a way to go to that British prison without getting arrested. And then I have to find out how to find wild ones. But I'm going to get them all."
"I wonder if I can work from far away. Maybe I should try sending my glowy person to Azkaban from here. You know, with a message. For the dementors. 'Goodbye forever'."