As I've made clear elsewhere, I'm writing my current WiP in close 3rd, single POV. Quite by accident I hit upon a slight problem with a major scene, which would result in a plot twist being given away, but behind my MC's back. Do I need to find a way to avoid this at all costs, or could it actually be a useful devise?
Othello believes at first that Iago is loyal to him, and Iago monologuing to the audience about how he's going to destroy Othello's life for no reason sounds like a pretty good sized plot twist if I remember right I think we could probably start a massive list of stories where a side character learns a secret from the antagonist that turns the story on it's head, but dies before being able to tell the MC anything. EDIT: oh, "single POV." Hmm...
