In the Kingdom of the Pleiades, the greatest chess game in the galaxy is about to begin. King Geoffrey of the Pleiades is dead. His daughter, Princess Jessamine, is meant to succeed him. But one of King Geoffrey's ministers is determined to play kingmaker and has concocted a fiendishly ingenious plan to block the succession and place his own candidate on the throne. To stop him, Jessamine's children, Alex, Alice and Ellen, are going to have to go on a journey across the galaxy, to a dangerous, abandoned planet in search of a long-lost artefact that once belonged to the greatest chess player in history, which they might just be able to use to help their mother. Their search will not be easy and, even if they can find it, they will have to face greater dangers than they have ever imagined on the ancient, treacherous planet known as Earth.