Like other books by this pair, it’s got cute illustrations to draw the kids in and a good message delivered through a story appealing enough to make the message palatable.  The message in this one: the perils of being a slob.  Sentenced to his room until he’s willing to pick up after himself, young Angus quite contentedly continues making messes, until a mountain of mess begins to grow on his bed, requiring him to use his climbing gear to get to the top to sleep each night.  But as the mountain of mess continues to grow, Angus finds himself approaching the surface of the loch, bringing him into range of scary land-monsters, which finally gives him the motivation to tidy up.