The Star of the Yshan Kings — Michael Davies

When twins Kyle and Sophie arrive at the school, there is something clearly different about them. But despite Sophie's antagonism, they are befriended by Josh, Charlie (Charlotte) and the youngest, Henry aged nine. Kyle and Sophie are more than just different; they are the children of the Galactic Emperor and their mission is to seek out the mysterious, sentient crystal, the Star of the Yshan Kings which has guided the Empire for 5,000 years. It was stolen from the Empire Capitol twelve years ago together with the Emperor's son who was just a toddler at the time and signs have been detected of the Star on Earth. Josh, Charlie and Henry are drawn into the hunt and must face incredible dangers and draw on all their courage and intelligence before the final discovery of a truth that is far beyond what anybody's imagination could have anticipated