In 1870, in the Spanish Philippines, the commandant of an island penal colony, aided by an American doctor and local villagers, decides to relocate his coastal camp to a fertile valley inland but the arduous trek is fraught with dangers.

A fisherman is found strangled and investigators come to believe it may have been by the irradiated skeleton that was found near his body. The film is often erroneously listed as an alternative title for 1971's "Blood Thirst."