Stevenson (A Village Full of Valentines, 1995, etc.) has written a breezy adventure in traditional comic book format, with his characteristically sketchy black pen drawings, loosely filled in with pale watercolors. Hubie, the youngest brother in a fashionably dressed family of mice traveling by train to the 1939 World's Fair in New York, takes snapshots of everything he sees. He gets off the train when it stops at night and then accidentally boards the California Comet, headed in the opposite direction. After a series of adventures, he gets flown to the World's Fair by Betty Beagle, ``the world-famous aviatrix.'' The story—which is as sketchy as the pictures and has an equally effortless quality—conveys a precise sense of the time and place (in various settings, e.g., mountains, desert, city), but its best moments come from Hubie's sarcastic asides and subtle one- liners. On the one hand, the format subordinates the text to the pictures, but on the other hand, these pictures belong to that variety of comic book in which the text is the main thing. As a result, readers can't linger on either the pictures or the text; Stevenson simply carries them away. A fast, enjoyable read. (Picture book. 4+)