In the shadowy underbelly of 1940s New York, a notorious thief has stolen the Earth Star — a mysterious jewel of incredible power and value.

The theft draws the attention of Seth Martell, a respected military leader, when his three sons become the prime suspects. Their pursuit of the truth leads them deep beneath the Sahara Desert to Sub-Sahara, where ancient secrets lurk in underground caverns. Here, the descendants of a lost civilization guard technologies beyond imagination, while strange hybrid creatures stalk the darkness.

As forces gather to recover the priceless gem, the brothers face impossible choices in Henry Kuttner's thrilling tale of adventure and betrayal.