I was on the quest in Act 2, The Darkest Dusk. It told me to listen to my surroundings, but nothing happened and the locked door in front of me didn't open.
After logging out, then back in, now the game has put me back to the very beginning of Act 1.
I'm not going to continue playing on that character in fear that might break it more, but if there's a way to fix it I would certainly appreciate it.