The Professor said:
Unless a game effect has caused you to draw an additional Mythos card, this is impossible. You draw a Mythos card basically before the investigators start their part of the turn, so that on investigators' turn 1 only the first Mythos card has been drawn, on turn 2 the second Mythos card has been drawn and so on... on investigators' turn 21 the 21st Mythos card has been drawn, and by the time you draw your 22nd Mythos card investigators can no longer take any actions before their turn 22. Thus, the turn you're on is equal to the number of Mythos cards drawn until the Mythos phase starts.
So, which one was it, 22nd Turn/Mythos card or 21st Turn/Mythos card? Just a minor issue to nitpick, I know, but it stood out in an otherwise accurate and well-written report that made me want to play AH again, so thanks for that.
-Villain