Johnny on the Spot

Vigorous illustrations of 1920s scenes animate this uneven melodrama, a blend of nostalgia and science fiction. Johnny, a youth wearing knickers and argyle socks, follows broadcast adventure serials. When his beloved radio gives up the ghost, Johnny takes it to an inventor for repairs. The man doesn't know much about appliances: ""My specialty is time travel,"" he says. But he applies ""a small charge of electrostatic magnetism,"" and the radio revives. Better yet, it now announces the news a day in advance (a la TV's Early Edition). Johnny earns his ""on the spot"" nickname by showing up at the scene of a bank holdup and a fire (and helping out), but the lure of easy money threatens on a day at the races (""It's not gambling... We know which horse will win,"" the inventor begs). Sorel, known for his New Yorker cover art, constructs an enticing cinematic world of brownstones and sepia-tinted interiors. His gestural scribbles of ink, applied in darting and sweeping zigzags, give the impression of rapid progress, while his earth-tone watercolor palette suggests budding technology. Yet the plot fails to ignite, then wraps up too neatly. The time-travel genre cliches (the boy, the eccentric inventor, the discovery, the abuse of power) recall the convoluted plots of radio shows, but Johnny's moral dilemma is solved too readily when his parents junk the ""broken"" Zenith and buy a Philco. Ages 5-9. (Oct.)