I found this a brisker read than Leah. Richard Hannay is an Englishman who has made his pile in South Africa, and returned to England. He is very soon bored to tears and considering returning to South Africa, when he finds himself caught up in events that will culminate in WWI. He finds himself dashing across England, pursued by both the authorities who suspect him of murder, and the German agents whose plans he has stumbled upon.
There are two more Richard Hannay novels besides the ones available here - _The Three Hostages_ and _The Island of Sheep_ - available at Project Gutenberg Australia.