Frustrating his sister with his tendency to transform into a monkey whenever he gets hyper, Clyde is given an extra-firm reason to try to control his energetic behavior when a new school principal moves into the neighborhood.

When eleven-year-old Sam gets into trouble and is forced to work for his reclusive neighbor Mr. Wells, he soon finds out that his mysterious new acquaintance hides many secrets of his own--including one that will change Sam's life forever.