Amy and Christopher, the Frequent Flyer Twins, are on their way from Singapore to Cairns, where the International Games are going to be held. But more than one lot of games are being played! 

Amy and Christopher have heard that someone is smuggling steroids in on their flight. All passengers are suspects. So are the airline staff. 

Something doesn't add up, but what is it? The Frequent Flyer Twins are just the people to find out.