[ She is about to ask about the extra uncle (extra uncle????) but Mabel's looking depressed again, so Otome just gently tugs her against her side in a one-armed hug. ]

Obviously none of us here are your brother or an extra uncle, but I think there are definitely people, myself included, who'd love to figure out this particular mystery with you. And then we can wrap it up, head home, and you can tell your twin all about it. I can't promise he might not be jealous, but...

[ Should have shown up otherwise, Dipper!! ]