Alright, so I kind of asked for this one. There's no less than five necromancer settlements nearby. I pretty much picked this site for the specific purpose of entertaining some undead guests. I am nevertheless somewhat disappointed by their sense of timing. I hadn't even sent the invitations! Such rudeness really cannot be tolerated, what would the neighbours think? I can't have zombies wandering around at all hours disturbing the traders. There is a time and a place for such shenanigans, and though the place is most certainly here, the time is not now.
I'm a little stuck though, and therein lies the problem. Normally I'd just seal the entrance against all comers and knuckle down for the long haul - it's not like I'm short on supplies - but the aforementioned traders are locked in here with me. I'm rather keen to keep my fellow dwarves alive, but I can't let them out. There's more than fifty zombies out there along with three necromancers to keep them coming. Those are not dwarf-friendly odds. My current military consists of somewhere in the region of approximately zero dwarves, and I do not have time to train and equip soldiers before the caravan will fall to insanity. My depot is secure if it comes to it, but I'd rather avoid such losses.
Clearly, if the merchants are to be saved, I shall have to get creative. My caverns are.....strange, with significantly more vertical space than lateral, so digging a subterranean exit is going to be time consuming if it's even viable at all, and I have no great wish to exploit my entrance bridge as a weapon (though should no other options present themselves, I shall have to rig something of that description together).
And so I bring this conundrum to the forums. What ingenious methods can you devise for me to rain lasting destruction upon the undead without exposing my dwarves to undue harm? My main concern is the necromancers. I am confident that if I can remove them from the equation, the caravan will be able to cut itself a path to freedom.
tl;dr Zombies and necromancers, no existing military, time is of the essence. Ideas?