If you've never seen or heard of either, the basic premise is that Aliens have come to South Africa and decided to stay. Unlike most other scifi movies, these aliens are not exactly the top of food chain. They do have advanced weapons but are also vulnerable to human weapons. So after being classified as refugees all type of scenarios playout. One example is the start of a blackmarket between the human slumlords and the aliens. The alive in Joburg has a theme of xenophobia running throughout it, which looks to be the same in District 9 too.