You are sure to draw some giggles with this story of seven-year-old Jonathan's strange adventure on flu-shot day. Dr. Mack is giving out a helium balloon with every shot, but Jonathan's little brother Sam makes such a fuss over his shot that the doctor rushes through Jonathan's just to get rid of the family. As might be anticipated--it's been squarely set up--he shoots medicine into Jonathan's balloon and helium into Jonathan's arm. Once outdoors, along comes big Duke Duncan, eight, who's been threatening to beat Jonathan up. But just as Duke takes a swing, up goes Jonathan. And when the police come with long ladders to bring him down, he just pops back up above the rooftops. Actually, Jonathan has a pretty good time floating around that day and the next. The only flaw in the fun is Duke keeping a constant eye on him from down on the sidewalk. But once the helium has leaked from Jonathan's ears and he hits ground, he finds that Duke is following him just to share the glory: "I was the very first one to see him go up!" Naylor's writing isn't as buoyant as her hero, but kids will connect with the fantasy.