Amiable thirty-sixth-century teen spy Jak Jinnaka hops to it when ex-girlfriend Sesh, now Princess Shyf of Greenworld, beseeches him to come help her with a few hazily described problems. Recruiting his friend Dujuv Gonzawara and Duj's just-ex-girlfriend, Jak decamps for Greenworld, where the three are dismayed to find Shyf a cruel, disdainful ruler. Pulled into a sexual and political snarl, Jak grasps harsh reality when he realizes his world supports Shyf, even when her drive for power includes murdering her father. Fortunately, when Jak reunites with his formidable alien friend, Shadow on the Frost, fierce combat follows, leading to the friends' violent expulsion to Mercury, where Jak stumbles into another deadly struggle. In this satisfying sequel to The Duke of Uranium [BKL S 1 02], Jak has to comprehend and value different cultures and races, gets in situations in which even the best action casts a bad light on him, and sees friendships suffer when he follows his conscience. Dialog and characters remain riveting, and Barnes injects a little libertarianism to mull over.