'Mission Invent' explores machines and engineering. Readers must use their problem-solving skills in a twisting-turning world of toys and puzzles: You love being an apprentice designer at Toy Towers, where they make the world's most amazing toys. You arrive one morning to find My Jollypops' assistant waiting for you. She tells you that Mr Jollypops wants to see you urgently - all will be explained when you get there.