The rousing action of John Marsden’s “Tomorrow” series continues in this sixth installment of his continuing saga in which Australia is conquered by an unnamed foreign army. This time Ellie and her teenage guerrilla fighters encounter a problem more difficult than combat: they become the guardians of the five children they first encountered in Burning for Revenge (2000). She foils an attempt by soldiers to arrest them and blazes off in a dramatic car chase. The children, however, don’t appreciate the help. They trek off into the bush, forcing the teens to track them down before they die of thirst. More implausible but gripping action ensues when Ellie and Homer raid an enemy house for food, then fight a ferocious gun battle. Marsden has shown himself to be one of the more insightful of YA authors with such titles as So Much to Tell You (1987). His flowing writing style adapts well to the action genre, yet he doesn’t abandon his exploration of adolescent trauma here. He juxtaposes Ellie’s metamorphosis into a hardened, bitter fighter with the transformation of innocent children into suspicious, feral creatures. Young readers can enjoy this series for the action alone, but those looking for greater depth will be satisfied as well. Marsden demonstrates that action books don’t have to be trash. (glossary of Australian slang) (Fiction. YA)