内容简介：
The first book in the award-winning Shadows of Time series introduces John Roley, Tim Jackson, and 2 inteligent computer prototypes known as ISAC-9. During their vacation, they are surprised to find that they have been proclaimed to be the guardians of time, a confusing situation since none of them had even been aware they were up for consideration. Before they have a chance to fully absorb this information (or decline the offer) they are thrown back in time to a point near the end of Mayan civilization. Immediately John is captured by Mayans, Tim is rescued by a group of people whose technology has no business existing anywhere, and both discover that real history is considerably more messed up than anyone could have imagined.