it's 10 years after the first one, jake pentecost (john boyega) is a professional thief of some sort and doesn't want to pilots jaegers because reasons. there hasn't been a kaiju seen since the breach was closed and he jaeger program is about to be shut down, although they'd had a huge budget previously and the world was working together, instead of "this is china's jaeger, this is russia's jaeger, etc). meanwhile, the black market is pissed because kaiju parts were selling for so much, but there's no pieces left to sell so they make their own jaeger(s) and open the breach back up (this is the black jaeger we see gipsy avenger fighting in the trailers). mako has to get jake (her brother) to come back and pilot a jaeger to save the world, and his best friend (scott eastwood) is his co-pilot. but for drama's sake, scott is pissed at jake because he left so they have to work through their feels to be a team again.
also, tony stark was able to build one in a cave... with a box of scraps. except instead of tony stark, it's a 15 year old girl, and instead of a cave it's a junk yard. she also is able to pilot this jaeger by herself, and she doesn't realize how amazeballs that is.
the plot sounds contrived. that being said, the director has also gone on record saying that GDT is basically sent everything for approval, so there's that. the director also directed spartacus so i'm VERY cautiously hopeful.