How many plot holes were left open after the ending of the series? Whether they are small or big, name them.
I know there were quite a lot but only a couple come to mind right now. Like the Tesseract episode. What happened to Professor Middleton and wht couldn't Lucas see the Tesseract. What was the significance of it? And why did the janitor express concern for Corrine's existence in Friction. And what happened to Avenir? There's a lot more I can't think of right now.