The basic premise:
1) Billionaire online RP game magnate/midwestern roughneck/former North American weed smuggler Richard Forthrast hangs out with adopted niece/Eritrean former refugee/brilliant engineer Zula & her computer genius/dickwad boyfriend Peter.
2) Peter makes an Epically Bad Decision.
3) Aspects of Uncle Richard's game come into play.
4) Zula & Peter are kidnapped by Russian Mobsters.
5) International intrigue/thrills/spills/espionage hijinks ensue.
As with most Stephenson books, I was principally amazed by his ability to keep approximately nineteen bazillion balls in the air in terms of plot & character arc--I have no idea how he manages it. Likewise, I'm always incredibly impressed with how well researched every single aspect of the story is, down to minute details of government, technology, architecture, geography, and camping equipment. (Er, or if it's not, he's a *really* convincing bullshitter!)
But what really made this book for me were all the kick-ass female characters. Like, more than one! With actual distinct personalities! Who, like, do badass stuff to move the plot forward and serve as more than love interests for the male characters! In general, international action/thriller/intrigue isn't particularly my bag, so I don't think that it's an exaggeration to say that, as well written as the book itself is, if those characters had been male (or if the women had been relegated to damsels in distress-slash-love interests), I probably wouldn't have stuck it out for 1,000+ pages, because, look, men running around with guns and crashing vehicles and hacking the interwebz and zzzzzzzzzzz.
So yeah. Like Neal Stephenson? You will not be disappointed. Never heard of Neal Stephenson but like a really smart, complex, well-written action/thriller/international espionage story? Give it a shot. Scared of 1,000+ page tomes? Can't help you there.