To steer back on course try these tips:
1. A few red herrings
2. Be very careful of balance…not to subtle “FLY YOU FOOLS!”….they never got it.
3. Never metagame plot points.
4. Not to obvious... “Is that a blade in your pocket or is that…”
5. If the players get the hint before you gave it, let them run with it, and leave the hint out.
6. Decide to take a break. If you are looking for a place to stop, take this time to break, and give them time to think about it.