People have unexplainably gone missing on Lake Amistad as it arises along the border between the United States and Mexico after the building of a dam on the Rio Grande River in south Texas. Ryan Shaw, a special agent for U.S. Customs, gets drawn into the dangerous mystery even though it's not part of his official duties.He's back along the border where he served for many earlier years, this time on special assignment from his current post in Washington,...