THE SECRET OF MR. M.
Three schoolchildren get lost in a walled garden where a mysterious man in an old-fashioned costume is conducting scientific experiments with his strange apparatus. Who is he, and why does he know nothing about ordinary modern things like traffic lights and tennis balls? And where is a curious balloon with its mysterious message heading? To top it all off, old spectacles and a walking stick have been stolen from the Natural History Museum. The trio must discover the identity of the man and also what peas have to do with it all?