Running away with the unhappy heir to the galaxy's biggest fortune, even if it's because he wants it, is bound to cause some problems. On the lam with the Caliphette of Iksaladam, Valerian and Laureline are relentlessly pursued by the Quatuor Mortis, who are still after the enormous reward offered for the child's safe return. Stranded among the Asteroids of Shimballil, they must evade the hunters, recover their ship, dodge profiteers and traitors ... and decide what to do with the little brat!