When young Arthur learns that his friend Tom has stumbled onto a crime scene and had a close encounter with the strange perpetrators, he rushes to visit his friend and to learn more about the events of the day. Then, a dark stranger pretending to be Tom's Uncle Jeremy leaves a mysterious package containing a mind-controlling potion for Tom and so begins an adventure which none of those involved could have possibly imagined. The theft of some of GRiPPENHAM's famous Copper Beeches, the potion left by Uncle Jeremy and the appearance of strange folk bring suspicion and excitement to the otherwise calm and peaceful village of GRiPPENHAM. As the plot deepens, Tom, Arthur, Arthur's twin sister Ivy and their cousin Mildred are taken into a world of mystery and intrigue in both their native GRiPPENHAM and over into neighbouring Nuffingham. Can the four young people, aided by their eccentric professor Uncle Max, stop the wicked Jeremy Suregrip from developing more of his potion, which will enable him to take control of the minds of those who drink it? Will they find an antidote in time to save Tom's parents, who have drunk the potion, and will the Copper Beeches be returned to their rightful place in GRiPPENHAM?
This is an adventure filled with colourful characters and told with wry wit.