Replying to WORLD WAR III ?

We all know whats happening between North and South Korea at the moment, they've never been that close to open war since 1953 or something...

So yeah, I know it's more likely they'll find some diplomatic way to solve this, but they just might go all out and it won't be pretty. USA is bond to help them since they have an agreement signed back in the days. If and I say IF they go at war, there is 2 question mark:

Does North Korea have the Nuke ?
What side will China and Russia take ?

I mean, just imagine the worst possible scenario: a be a big fat world war with USA/EUROPE/SK/JAPAN/INDIA vs RUSSAI/CHINA/NK...
But again, Russia and China are more likely to choose the south korea side or just go neutral..  But even if there is 1% chance it would happen, it's still scary as fuck, even more knowing I'll be in China all summer.