Author(s): John Fardell
Sam and Marcia are back in Edinburgh with Zara, Ben and Professor Ampersand. The friends are helping to build an amazing electric-powered flying boat when they stumble across an old photograph - a clue that leads them on to the trail of a long-lost secret invention that could change the world. But a shadowy organisation is also after the invention. Soon the children are caught up in a perilous struggle that will take them through dimly-lit museum galleries, up into the skies above Europe, down to the murky depths of Lake Geneva, and into the heart of a fortified Swiss castle. This is a breathtaking adventure of encrypted messages, aerial chases and astonishing secrets from the author of "The 7 Professors Of The Far North".