More specifically, a war that involves 90% of the world’s population, and happens to break out on your homeland
I’d be jolly surprised if WWIII broke out in my country, because Ireland is neutral.
OTOH, if the nuclear football has AutoComplete on its targeting software, Ireland has the same two first letters as Iran and Iraq, so …. I wouldn’t do anything, because I’d be just so much radioactive dust.
Otherwise, I think I’d be fine. I have an open fire in my house, a quarter-share in a turf-bog, nearby forestry and water, and a nice big paddock in which I could grow vegetables and maybe keep a sheep or a pig for slaughter and some chickens. There’s a donkey sanctuary near me, and they’d probably let me have one for transport – it could share the paddock with the sheep and the pig. I knit, crochet, spin, felt, and sew, so I’d be okay for clothes – shoes might be harder if supplies run out, but I know someone who can make Viking-era shoes from raw leather.
I’m not sure how I would manage without my meds if it got to the point that the healthcare system disappeared – I could probably make a painkiller from willow bark, but thyroxine would be more difficult. And yucky. I’d miss coffee, but could have a bash at making a substitute from acorns. I have oodles of books, including tech and professional books, so the offspring would get an education, and I might not go stark staring mad as quickly.
If the country did get overrun, I’m too old to join up and fight, but I’m a good shot and have a fair idea of where I could get my hands on some shooty-bang-bangs. Also, you know how kids can be about dinosaurs, the obsession and all-knowingness? That was me about military battles and campaigns (and not just because dinosaurs roamed the earth when I was a kid, and were, like, BBOOOOORRRINNNNG), so I could probably plan a defence at least. Lots of big holes and paling posts, for starters:
And, courtesy of the Troubles and high-school chemistry, I know roughly how to make explosives from my kitchen cupboard (well, from the nearest farmer’s shed, really).
I’d miss the internet. God I would miss the internet…
So the first thing I would do would probably be, have a cup of coffee and start planning. And print everything off the internet that I could think of that might be useful.