I'm searching for a story, I believe it was a novel, in which someone answers an ad, and meets up with a group of different people in some suburban strip mall basement ( I may be completely misremembering this, however) And I think after some selection process, a smaller group is basically hired to steal something. One of them is a young girl. Maybe she's named Kitty or Fox, maybe not. And I think they steal a golden ball, possibly it's a magic enhancer or something.  (There's a definite chance I might be conflating two books) Because, there's a group that tries to summon a god (our modern world) and at some point, they're all in some Chateau in France, and they do a lot of research. And in the end, they're successful, maybe the God is called Fox. Anyway, he kills the old professor type and everybody in the group. Only the young girl remains alive. But not unscathed. (The god ..... her) Maybe that's her backstory, before we meet her.

I'm searching for a story, I believe it was a novel, in which someone answers an ad, and meets up with a group of different people in some suburban strip mall basement (I may be completely misremembering this, however). I think after some selection process, a smaller group is basically hired to steal something. One of them is a young girl. Maybe she's named Kitty or Fox, maybe not. And I think they steal a golden ball, possibly it's a magic enhancer or something.  (There's a definite chance I might be conflating two books).

Because, there's a group that tries to summon a god (our modern world) and at some point, they're all in some Chateau in France, and they do a lot of research. And in the end, they're successful, maybe the God is called Fox. Anyway, he kills the old professor type and everybody in the group. Only the young girl remains alive. But not unscathed. (The god ..... her). Maybe that's her backstory, before we meet her.