Long description:

The Code Breakers have a happy reunion with Stephie, their friend from Hong Kong, that is, until she is mysteriously kidnapped one night. What are her ruthless kidnappers after and why does everything resemble a computer game? Will The Code Breakers be able to conquer the eerie Gatekeeper's challenge and uncover the sinister plot?Join The Code Breakers as they tackle exciting puzzles that lead to deeper investigation and intrigue! Matthew, Bell and Jimmy have always loved Maths. Little did they know that their hobby would eventually lead them to work with the police, take them to different countries and meet with all sorts of dangers that would test them to their limits!Each book in the series is a new adventure that invites readers to help solve Maths puzzles and codes, together with the three friends. Solutions are provided, and the stories also come with interesting and educational fun facts to grab the interest of readers.