Murphy is the sole survivor of his crew, that has been massacred by a German U-Boat in the closing days of World War II. He is rescued, and ends up at a forgotten mission station near the mouth of the Orinoco, and begins to plot his vengeance. He wishes to sink the U-Boat by means of any method imaginable to him, and sets about to make the courageous attempt, assisted by Louis, the administrator of the local oil company.
Under the pretense of having a picnic, a geologist takes his teenage daughter and 6-year-old son into the Australian outback and attempts to shoot them. When he fails, he turns the gun on himself, and the two city-bred children must contend with harsh wilderness alone. They are saved by a chance encounter with an Aboriginal boy who shows them how to survive, and in the process underscores the disharmony between nature and modern life.