Pacific Rim came out back in 2013 and it hasn't been the sort of franchise to keep itself current by inundating us with media over the last six years. As such, it's very likely that even if you saw Pacific Rim back then, and even if you liked it, the story has probably faded from your memory beyond the basic set up of "giant robots vs giant monsters."
To be sure, "giant robots vs giant monsters" sums up Pacific Rim pretty well, and considering how few members of the first movie's cast will be returning, the sequel is likely to go off in its own direction. However, it will still be building on the events of the first movie, so here's a refresher course going into this weekend's Pacific Rim Uprising. Here are the key things to keep in mind.
The Kaiju War
The story of Pacific Rim starts in 2013, which is when, in this timeline, the first Kaiju appeared to wreak havoc on Earth. The planet banded together to create the Jaegers, massive robots used to fight and defeat the Kaiju. We then cut to seven years later to see the Kaiju adapt their attacks to overcome the Jaegers, killing Yancy, the brother of Raleigh Becket, the first film's lead character played by Charlie Hunnam. We then jump an additional five years into the future to watch humanity's last stand against the Kaiju. This put the end of the first movie in 2020, making the sequel take place sometime later.
Jaegers, from the German word for hunter -- as the movie makes sure to tell you -- are massive robots piloted by humans almost as a large exoskeleton. The pilots move their legs to walk the Jaegers and swing their arms to punch the Kaiju. Each Jaeger has a pair of pilots because it was discovered that a single pilot couldn't handle the mental load of piloting alone. The two pilots are mentally synced together via a process called drift, that allows them to work together seamlessly. However, this process also gives pilots a peek into the mind and the memories of each other. This means pilots have to be willing to get very close personally so compatibility is important.