I played through the prolog in Westmark(Westmarch ?) and got 15 soldiers. After the lighthouse, and visit to Defender of Souls, there are 5 left. Next mission: Destroy the Invaders. Huh??? It says to use the base to build an army, but before I can get even a single new soildier, a powerful army of 15-20 undead,, some higher level than the avatar, first attack and kill anyone in Westmark near the Lt. and then cross the river to destroy the base. This is crazy and impossible to survive. Game over and reloading seems useless. How did anyone ever get any further?

If I go to the northern village for the side quest, the party survives but it is game over anyway when the base is destroyed.

Havn't played that one yet, good to know it is tricky.

I have learn't some tricks from playing shadow wars that may or may not work here....

1) send some workers off to obscure corners of the map just in case your base is destroyed. I'm not sure exactly how this works but in some missions where my HQ was destroyed and i lost, i have restarted the mission and even though my HQ got destroyed again just by having a hidden worker, the mission was allowed to continue!

2) Attack the AI silver mining operation, even if you have to run past towers to get to it. This will draw back all AI attackers (from that camp) relieving your base and the AI cannot cope having its silver cut off, it will quickly run out of workers and cannot build more, it is a dead AI walking at that point, you can run away from the returning armies if need be, you have already won!

3) Try to do as much as you can before initiating any quests.... that is, touching any yellow exclamation marks, question marks, entering yellow circles with the dot in the middle... anything at all quest related.... thus avoiding AI triggers. And when you do initiate quests, SAVE the game before hand!
Further more on this point, clearing as many enemies before triggering the AI can make point number 2 above, all that much easier to achieve.

4) I find the most effective quick defense is your team backed up by at least 3 towers. Then all you need is at least five or more low level melee units to take your teams place so your team is free too run off and do all those important things they need to do. But that is a very minimum defense, you will still need to build it up more to try and avoid having to keep replacing towers and units to maintain the defense.

5) always save the game at the end of every mission, sometimes when you begin a new mission, the game will not give you time to adjust the equipment fit out of your team, you need to reload the saved game, then take all the time you need to adjust your equipment fit out before restarting the new mission.