Let's figure stuff out! :3 I am always in favour of more CR. Anton and Callaghan seem like pretty good friends, so Skulduggery's probably heard of or at least seen Callaghan around the Hotel.

For the record, Skulduggery wouldn't be setting out to arrest anyone, what with the only form of law enforcement/prison being the Snakes. He'd take things as they come, and be more likely to confront Callaghan than accuse him of wrongdoing - so long as no one gets killed.

Did you have a last clue or a timeline in mind?