On the Franco-Austrian Frontier during World War I, an Oriental priest, chaplain of a French colonial regiment, is condemned to life imprisonment because he possesses the power to turn men into zombies. In his prison cell, the priest prepares to burn a parchment containing the location of the secret formula. Gen. Mazovia (Roy D'Arcy) kills the priest and takes the partially burned parchment. After the war, an expedition of representatives from the Allied countries with colonial interests are sent to Cambodia to find and destroy forever the so-called "Secret of the Zombies". The group includes Colonel Mazovia; a student of dead languages, Armand Louque (Dean Jagger); Englishman Clifford Grayson (Robert Noland); General Duval (George Cleveland); and his daughter Claire (Dorothy Stone).