The cover art is of Fangetta, Braxus, and Thickhead McBrick on board a ship, and Fangetta is holding King Groosum's T. rex Crown Jewels while Braxus is eating meat with his foot. In this book, the crew of the Sauropod are lured onto a strange spaceship by a fake distress call and are captured by the Royal Rex Police, who catch them with the T. rex Crown Jewels. After a short trial at the Claw Court on Teerex Major, the T. rexes lock the astrosaurs in St. Bonecracker's Prison, which is ruled by the fearsome Fangetta and her robot warders. It's up to Arx and Iggy to help their friends escape from the T. rexes before they get eaten!