The idea that he thought she was joking brings a smile to her face, but she shakes her head in response.

"Nope. We really were sitting on top of a Hellmouth."

Which brings them smack into the reason she became a witch in the first place, but, uh... that's not really where she wants to go with this conversation.

"Giles used to say there was one in Cleveland, too, but we never found out if that was real or not."