Juvenile fiction with sustained action and an exciting mystery plot so skillfully written it will appeal equally to guys and girls. Sibling sleuths, Arthur and Kristin Davis come face-to-face with the "big time" when Madame Dragonfly hires them to give her information on the Autumn Rose, which they believe is just a nearby horse farm. But it isn't, and they aren't the only ones who know what the real Autumn Rose is.

"Who would've guessed that a 150-year-old mystery could be so dangerous? While the sibling sleuths of the Davis Detective agency, Arthur and Kirstin Davis, are visiting their uncle in San Francisco, a chance conversation at a baseball game puts them on the trail of 400 pounds of gold that vanished during the Gold Rush. But the teen detectives soon discover that someone wants them off the case. The investigation quickly becomes a harrowing adventureoexploring the treacherous old gold fields, scuba diving in the shark infested waters of the San Francisco Bay, and managing to get inside one of the buried ships. But things really get dangerous when they finally uncover the secret of the lost treasure of Fernando Montoya.