It's a perfectly fair question, and of all the people she could ask, right now Booth is the best person. He's present, for one, but also the least deeply impacted by Zach's betrayal.

"He met Gormogon at a conference, and they became friendly. Gormogon used logic to entice Zach - said secret societies are evil, that they should end them for the greater good. I don't know that it really makes sense to anyone but Brennan, but Hodgins is blaming himself for that part, too. Since he kept talking about conspiracies and secret societies and...you know. Things like that."