When twelve-year-old Alex receives an old tin robot in the post, the note from his grandfather simply reads: 'This one is special'. But as strange events start occurring around him, it doesn't take Alex long to suspect that the small toy is more than special; it might also be deadly.

Just as things are getting out of hand, Alex's grandfather arrives, whisking him away from his otherwise humdrum life and into a world of strange, macabre magic. From Paris to Prague, they flee across snowy Europe in a quest to unravel the riddle of the little robot, and outwit relentless assassins of the human and mechanical kind. How does Alex's grandfather know them? And can Alex safely harness the robot's power, or will it fall into the wrong, wicked hands?