I think Vicky may be a classic spy story character, like a Mary Sue in a fan fiction, but I don't know the word for it. You've got Spy A and Spy B, telling all the world they're on opposite sides, while all the time, unbeknownst to all but themselves, they're on the same side. They can't meet lest somebody see them and learn their deep dark secret. So they pass messages via an unsuspecting third party because the unsuspecting third party - call her, for argument's sake, Vicky - can't keep her mouth shut to save her life, and Spy A - call him, for argument's sake, Roger - knows that whatever he tells Vicky will be told to Spy B, and Spy B - call him, for argument's sake, Burke - knows that whatever he tells Vicky will told to Spy A. Clearly Roger and Burke conspired together to kill Bill Malloy and are now conspiring together to drive Sam Evans mad. The motive has not been revealed yet, but I'm patient.