Jan Tleskac was an apprentice locksmith who claimed to have invented a flying bicycle. He met his death in mysterious circumstances, falling from the tower of St Jacob’s church. Years later, an old suitcase was found containing Tleskac’s diary. The diary made reference to a mysterious puzzle which Tleskak called “The Hedgehog in the Cage” and directions to an abandoned clubhouse. Could this hold the secret to Tleskac’s invention?