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.

In the Kingdom of the Seven Stars, the greatest chess game in the galaxy is about to continue... Four hundred years ago, King Stephen Tarquin, the founder of the Kingdom of the Pleiades, made a promise to a dying scientist. His descendants have kept it ever since. But now, Lord Damon Blackstar, who has a new plan to overthrow Queen Jessamine and put his own candidate on the throne of the seven stars, is going break it. To save their mother, Jessamine's children, Alex, Alice and Ellen and their bodyguard Captain Zachary, must once again travel across the galaxy, on the trail of the most dangerous space pirate in Pleiadean history, who once stole the only thing that could stop Lord Blackstar's plan. But before they can find it, they will have to survive the deadliest plants in the known universe.

In the greatest chess game in the galaxy, a new move has just become possible... Queen Jessamine Tarquin and her children are visiting Indigo, an ocean planet in the Kingdom of the Pleiades. They are looking forward to a relaxing holiday and to enjoying a local festival. But when a secret hidden by one of their ancestors is suddenly revealed, Lord Damon Blackstar is presented with a golden new opportunity to force Jessamine to abdicate and place someone he can control on the throne. Jessamine's children, Alex and his sisters Alice and Ellen, and their bodyguard Captain Zachary, with help from their favourite relative and their school friends, have one week to do two things. They must follow and solve a trail of clues left by their ancestor across Indigo to stop Lord Blackstar, and ensure the festival can begin on schedule by staging a Shakespeare play. Even with help from unexpected sources, it is going to be a long week until the curtain rises.