[The secret mission. Today at the campsite, there's a comic convention cosplay event. I've brought the gear, and the goal is to somehow get Sophie into a cosplay outfit and make an appearance at the event. You want to see Sophie in cosplay too, right?]
This was the message Isabella had sent to herself before leaving home, the so-called secret mission.
As for the barbecue and everything else earlier, it was all a setup for this moment.
Of course, Sam knew Sophie's temperament all too well. It was hard enough to get her to go to crowded places, let alone have her dress up in 'fancy dress' and show up at a cosplay event.
For her, it might be akin to social suicide.
She wouldn't find the idea of basking in adulation appealing.