Twelve-year-old Lewis Castorman is a master locksmith: there is no lock on earth that he is unable to open. He is therefore flattered when world-renowned chemist Ernst K. Grumpel invites him to his office in New York City and offers him a lock-picking assignment. His confidence quickly turns to dismay, however, when he learns this job will take him to Yellow Swamp in northern Alberta, the scene of a disastrous chemical spill a year earlier. He is also horrified to discover that Grumpel is utterly ruthless and, through his chemical inventions, can alter the rules of nature at his will. But the assignment is one that Lewis can't refuse.

How is Grumpel able to create such miraculous transformations? What secrets has he locked away and why has he taken pains to store them in Alberta? Despite the strange discoveries Lewis will make at every turn in his adventures, nothing will prepare him for the final encounter that awaits him in Yellow Swamp.