Jordan McArthur and Vivianne Blackstone have to work together to save Earth and the galaxy from the Tribes machinations. Vivianne is an Earth dweller while Jordan is from another planet. Jordan has infiltrated Vivianne's business in order to help create the spaceship that is going to save the world. All kinds of things go wrong when Jordan launches the ship prematurely with an untrained crew.
I enjoyed this series and it's connection with Merlin and the Holy Grail. Though this installment wasn't as good as the others. A little too far-fetched and improbable to be believable. I really liked Jordan's character and Vivanne's tenacity.