Book excerpt: When a tip comes in of a threat against the "Circus of the Super-Stars" that they are performing in as well as a series of crimes elsewhere coinciding at same time, the Super-Friends employ a set of circus performers as a duplicate set of Super-Friends to meet the challenge. But which job will the imposters be doing - circus performing or crook-catching? See if you can spot the clues and tell which ones are the real Super-Friends.