Who are the Twindicate? What do they want? And can Si the Spy stop their dastardly plans in time? Usborne's classic spy hero returns in a new adventure! Look out for him in a crowded train station, a thronging carnival, a shopping mall, a science lab and of course a secret underground villain lair. As well as spotting our hero on every page, he'll need your help cracking codes, solving puzzles and unraveling fiendish conundrums to get to the bottom of an international crime conspiracy.