So we played this quest yesterday and really enjoyed it. Except there was a time conflict moment. There are two "at the end of the Overlord's turn" moments.
It says, at the end of the OL turn, if Serena isn't rescued, the LO gets two fatiuge tokens.
It also says, at the end of the OL turn, if all heroes are adjustment to Serena, she is rescued.
So what triggers first? My Magic mind says that since it is my turn (I'm the OL) I get to choose what trigger happens first, since I have priority. Then I think of Arkham, where all time conflicts are resolved in the favor of the investigates.
We ended up playing it with giving me the fatiuge tokens. It gave me the win for the encounter two turns later. Even with that edge, I still lost the quest, but it was very close because of it.