This is a fascinating science-fiction about time travel. The story links a far past or distant future, advanced, scientific world of Eos with the 1906 San Francisco earthquake. The trouble starts when a young woman named Cheryl decides to marry without the permission of the Central Council. The scientists of the Council predict a disaster for Eos if this marriage goes forward. To prove their point to the doubtful Cheryl, they send a team of explorers into the distant past to search for clues to confirm the ancient Law of Reason.