Thunderhead — Douglas Preston; Lincoln Child

RUMBLES OF THE PAST
On an abandoned Santa Fe ranch a young archaeologist finds a letter written sixteen years ago yet, mysteriously, mailed only recently. In it her father, long believed dead, hints at a lost city of gold that will make him famous-and rich. Now Nora Kelly is leading an expedition into a harsh, remote corner of Utah's canyon country. Searching for her father and his discovery, Nora begins to unravel one of archaeology's greatest mysteries...

FLASHES OF DEATH
A thousand years ago a thriving civilization suddenly and mysteriously vanished. For Nora Kelly and her strife-ridden team of explorers, the answer is at their fingertips. Then the terror explodes ...