We just played Death on the Wing, and had a bit of a tricky time with the win conditions for part 1.
When a hero removes a boulder, the rules say it is "discarded". Does this mean;
a. If one or more boulders are removed by the heroes, the overlord can no longer win by having all the boulders "on the map at the same time" (as some have been discarded), and the Overlord can now win by trapping a hero.
b. The boulder is returned to the overlord's pool of boulders, and providing he has enough turns to do so can still win by having all the boulders on teh map at the same time