I once came across a book where the plot somewhat echoed that idea. A large group of contemporary people ended up/get stuck in a magical world. For a while, they tried to hold their own, but in the end, almost all of them were either enslaved or killed. I feel like even if it's an entire country, they're likely to face a similar fate, but it might take much more time. Without magical abilities and unaccustomed to such conditions, they'll have little chance of fitting in.