Can be any book. :) Just add the spoiler warning.. Or just say from wich book.

I liked the ending of the first book! ^^ The one where Skulduggery says something like; "You have that something, Valkyrie.. I don't know what it is. When I look at you it's like.."
Stephanie: "Do I remind you when you were on this age?"
Skulduggery: "Well, no. I was about to say that there's something really annoying about you, and sometimes I even doubt you're sense, but still I'm going to teach you. I like it when there's someone following me like a puppy. It prop up my self-confidence."

Sorry for the bad english.. I'm from Finland so I don't know exactly how it goes in English... <.<'