Master of magic question about Psionic Blast

So this week I have caught the Master of Magic virus again, what a great game. But how do you defend against the sorcery magic spell Psionic Blast? The AI rips my heroes apart with it, even when they have like 30 defense and all the megic immunity and whatnot stuff. Thats probably because on impossible level they have tons of mana and blast away with max extra mana.
This makes it literally impossible to play on impossible! But I want impossible because of the funner dungeons and towers. I even set magic on the weak setting, doesnt help much.
I can think of no defense. I work around it by setting "strategic combat only" on, then they come out alive...
Am I mising something, why is everyone complaining around cracks call, that one is no problem at all, I hate psionic blast!

 

http://www.gamefaqs.com/boards/564960-master-of-magic/49479990

Seems to have a decent answer.

 

well anyway its too much imbalanced spell

the problem is not defending against, the problem is attacking, often just in the first turn you end losing 1 hero even if well lvled and equipped

in some battle against nagas or other casting things you can lose 2 3 heroes just in the first turn without any counters

ofc in the late stages you can perma buff your heroes with defensive things but still its too much gamebreaking

any patch fixing it maybe?

 

Being invisible, you cannot be targetted spell by.