The third book in the gripping fantasy-adventure series, packed with code-breaking, cyber-technology and a boy hero with a supernatural destiny.

Full of magical code-breaking skills, non-stop action and a tech-savvy hero, this action-packed adventure is perfect for fans of Percy Jackson, Doctor Who and Alex Rider. Code breaking genius William Wenton is celebrating his thirteenth birthday when news breaks that Big Ben has suddenly stopped working.

This is the first clue in a series of puzzles and codes that will lead William to a network of long-lost underground tunnels beneath London, in pursuit of an ancient weapon of untold power. Secrets, danger and code-cracking abound in this thrilling fantasy-adventure that will push William's skills to the limit.

• The third adventure in the irresistibly cinematic and addictive series by a celebrated Norwegian film-writer and maker. 
• The series has sold to 36 territories around the world. Film rights sold to Oscar nominated film director Morten Tyldem (of The Imitation Game) and his production company Norse Code.