The year is 1837 and the location is the Thames-side Hamlet of Bray just up-river from the historic town of Windsor in England. Two exceptionally bright teenagers, Jack and Jill, meet up with a distinguished scientist and a famous engineer. The engineer challenges them with a puzzle and they are able to find the solution. They then turn the tables and challenge the distinguished adults with an imaginative puzzle of their own involving a beanstalk and what can be found at the top of it. This gives the scientist and the engineer a hill of their own to climb as they all have imaginative fun exploring the upper slopes of Mount Improbable. The story is an easygoing mix of ingredients: fiction, history, science, engineering, fantasy, puzzles and philosophy wrapped up in a detective story with a twist, in the twist, in the tail, of the tale. All the loose ends come together to deliver a coherent and profound moral that may surprise the reader as the true nature of the treasure is revealed.