Strange shakes his head. "I tried to scry for them directly after the concert, but I couldn't find anything."

Thanks, Void. And that's another thing that just pisses Strange off more than he wants to admit. Just once can his scrying not be interfered with via fae magic, shadow magic, or whatever the hell the magic used at the concert was. Just give him this one bit, universe.

"I've no idea how to even start searching for them. I imagine the magic will rebuff any sort of tracking spells as well."