Unfortunate Plot Hole needs fixing

[Lwaxy]

I know that I, and most of the players in most of my groups, would rather die/tpk due to their own mistakes than have Supernpc save them time and again.

Same here if it would happen again and again. However, my players would be annoyed big time if they tried hard and weren't totally dumb and I'd not give them a way out at least the first time, especially in an AP or with pre-planned adventures.

 

[anest1s]

As a DM I feel that my job is to tell what happens, and it must make sense.
However I feel that unexpected things that make sense are ok to happen too.

For example, the wizard was tricked: The spell he knows won't summon demons, but a deadly disease called "Demon Fever" (or something like that). He hasn't tried the spell before so he wouldn't know, and its very demon like to use lies to spread chaos end death. Then the PCs would get infected too of course, and they would die (if they failed to find a cure).

 

[Aran Thule]

Another option would be that the demons were summoned and all goes to plan.

Unfortunately the act of summoning demons started a nasty chain of events.

Soon after there murders and sightings as small demons starts appearing and vanishing within the town.

They could find a scroll explaining that the reason that Heironious blessed the town was that it was built over a weak point between the prime and the abyss.

The summoning has weakened the barrier and any time that things get summoned the barrier gets weaker and bigger things get through.

 

[Derren]

So the wizard summons demons which can't attack the town. Too bad that they can besiege it and now the PCs and all the civilians are trapped in the town and cut off from the rest of the world.