Led by Paula Martelo, The Terrible Ones are the widows of men executed for plotting to overthrow former Dominican dictator Rafael Trujillo.
Based on one of the clues supposedly referring to a castle or fortress of some kind, Tsing-fu is conducting excavations in the dungeons of the Citadelle Laferriere in Haiti.
Carter and Paula Martelo discover that the Citadelle is not the location of the buried treasure and head for Santo Domingo in the Dominican Republic.
With the help of The Terrible Ones, he plants the bodies of the fidelistas in the Chinese restaurant in Santo Domingo used as a front by Tsing-fu and retrieves a map showing the locations of planned short-range missile bases dotted around the Caribbean designed to control the sea passages and restrict US shipping – the true nature of Operation Blast.
The monastery has been attacked and overrun by Tsing-fu and his soldiers who have also discovered the true location of the treasure by tracking down and torturing former Trujillo aides.