Killers from the Cay — R.J. Price

In the summer of 1715, a Spanish ship spilled a load of silver coins in the Caribbean Sea. The recovery effort was too over-burdened to carry it all back to Spanish territory. So, they split up and left 350 thousand pieces of silver guarded by a skeleton crew on an unmapped island. But, when the sailors returning to safe harbor and the soldiers left to guard the treasure encounter a new threat, more horrific than anything they had ever encountered, they must figure out how to survive, or at least prevent it from spreading to the civilized world they left behind.