On an operating table, an unnamed patient undergoes open heart surgery. Pathologist Francis B. Gröss states to the viewer that he has become interested with the transitional periods of life and death thanks to a recurring dream. He has accrued footage from several parts of the world in an effort to better understand and study the many "faces of death". In Mexico, Gröss has captured the mummified corpses of the deceased inhabitants of Guanajuato, as well as footage of a dog fight between two pit bulls. He next examines the natural predators of the Amazon rainforest and the ways in which they kill their prey. Footage of a live monkey being killed and its brain being eaten by guests of a banquet is also shown. A man is killed by an alligator, an act that Gröss calls a "violent retaliation from a creature who has suffered continued abuse from mankind".