The Forerunner (The Forerunner #1)

Zed is a washed-up MMA fighter that is starting to realize that there isn't much of a future ahead of him. While hitting the bar with friends to forget his sorrows for a while, he meets an attractive woman who has an interesting story for him—aliens are going to take over the solar system in two years. Thinking that she is either crazy or he's had a few too many, Zed writes her off—until she shows him things that aren't possible, including healing his chronic injuries and showing him what she actually looks like (hint, not human).

There is no stopping the takeover, but humanity is going to be sent to an already populated planet and will have to find a way to survive in a hostile world. A few humans will be sent ahead to prepare the way, to give humanity a chance. They are the Forerunners.