The Secret of the Desert Stone — Frank E. Peretti

The soldiers stiffened at attention, but there was still a stirring in the ranks. Their faces held wide-eyed fear. Field Marshall Idi Nkromo turned with deliberate casualness and looked across the barren expanse of desert -- the same direction the army was looking. His saber fell from his trembling hand and clattered on the stones and sand.

Biblical archeologist Dr. Jacob Cooper arrives in Togwana with his children Jay and Lila and one goal -- to discover the secret behind the two-mile-high Stone that has mysteriously appeared overnight. Who could have excavated, carved, and transported the colossal Stone? The Coopers' uneasiness soon turns into dread as they are watched and threatened by the country's new government and brutal dictator ldi Nkromo.