About the Great Hunters

The Harvesters were professional predators with first-rate weaponry, thousands of years of experience, and devastatingly efficient tactics. For their defense, the humans had obsolete military technology, a pacifist alien exobiologist, water bears, and two young women who had been kicked out of high school. 

If Las Vegas were giving odds on the coming conflict, the Harvesters would be million-to-one favorites.