A year has now passed since Steeley floated off into the unknown in a balloon at the end of the first book, Sky High. Tubby and Brian Ballantyne have travelled to Paris to try out a new Puss Moth aircraft that Tubby has acquired. Finding a copy of a newspaper called the Continental Daily Mail, Tubby and Brian are intrigued to see part of it has been cut out. Their curiosity leads them to investigate what has been cut out and why. The article was about the kidnapping of an American woman called Virginia Marven. . . . Their adventure begins.