When Josh twists his ankle in a Games lesson, Brian invents a Valuxian cure for Josh's sports injury. However, as with most of Brian's inventions, something goes wrong and the gadget makes Josh a chess and maths genius. Josh then has a choice to make about whether the benefits of genius are outweighed by the drawbacks of geekdom... But while Josh has become a genius, Lucy feels miffed at losing her identity as the smart one in the family. Meanwhile, Mel's life of fun and clubbing seems so sorted that Sophie decides she wants to go along too. When Mel points out that she won't fit in, Sophie decides to find a new look - much to Mel's horror.