Time travel and its fascinating paradoxes get surprisingly slack treatment in the second episode (after Gunpowder Empire) of Turtledove's Crosstime Traffic series. Crosstimer Lawrence Gomes, a 21st-century entrepreneur who travels to alternate time lines to trade for goods and services, and his teenage son, Paul, sidestep to a world where Germany won WWI and still dominates the globe. They set up a shop called Curious Notions in San Francisco to sell electronic equipment, but their state-of-the-art wares quickly arouse the suspicions of both the occupying German constabulary and crime lords of the local Chinese triads. Plucky Paul complicates matters when he befriends Lucy Woo, a working girl whose family is inadvertently swept up in their cat-and-mouse game with the authorities. Turtledove does his usual fine job of developing the alternate history, but he lets other details slip: he never explains why Paul and his father, who hope to conduct business unobtrusively, call attention to themselves by selling blatantly futuristic goods, and he makes the Gomes's German and Chinese pursuers seem so easily outsmarted that the plot never develops tension or suspense. A finale in which Paul is saved from a predicament by miraculous intervention, rather than through his own resourcefulness, may disappoint the target audience of younger readers who might otherwise identify with its teenage hero and his colorful adventures.