Quantum theory posts the existence of a multiverse, and this story is set in one. There are hundreds of alternatives that you can travel to providing that you are dead in that alternative. That is what makes Cara so valuable because she is dead in most of them, and can travel between worlds meeting doppelgangers of people she knows in her world. That is also what makes her dangerous, because she knows who is evil, and stands up to them.
I open my mouth to give the company line, that we have been visited but they just haven't been detected, but they freeze. What if there are too few Adam Boschs who aren't bloodthirsty emperors? How many Nik Seniors let their eldest sons live? How many Adraniks killed their fathers and took their places?
I could tell her this, but I am not sure why she wants to know.
'I don't know. I never asked.'