Uh... well, the reason he came down to Earth - I mean his ship got shot down, but there's this other race of aliens that crawl in peoples' ears and take over their bodies. They kind of look like slugs. And they've been trying to invade my planet, but secretly, since they don't want to kill off potential hosts in a huge war.

And my friends and I have been holding them back for two years. There's only six of us. ... One of my friends is technically my uncle, since he's an alien too and isn't human, but still.