The Powers of Matthew Star

What is The Powers of Matthew Star about (plot, summary)
Quadris, twelve light years across the galaxy from Earth. It was home for us until an intergalactic armada conquered it. I fought by the royal family's side, but in vain. Even their remarkable powers weren't enough. The Crown Prince and I escaped to the nearest planet on which we could survive and further his powers in order to some day return to free his people.