Maxime Bellac owns an art gallery. He has an affair with Michelle. One night when they have dinner together, Maxime tells Michelle he is forced to leave for the Canaries because of paintings. When they take a walk after their meal,a man suddenly appears, revolver in hand. In self-defense, Maxime kills him and,much to his surprise, recognizes a national security agent.Maxime confesses that he is in the pay of an eastern power; his mission is to get a file concerning Western nuclear weapons. Because of his crime, he cannot carry out his job; for Maxime's love, Michelle takes his place and becomes a spy.

Roberto (Luigi Giuliani) and Luisa (Rocío Durcal) are a couple but are not as sincere as they should be. She tells him she works at Telefónica when she actually sells cigarettes at "The Green Windmill" cabaret. She's surprised when she discovers plans for a bachelor party there in honor of Roberto, who is marrying a wealthy heiress. In revenge, Luisa adopts the role of Luisito and faces Roberto in disguise.

As the Earth wrestles with its agonizing birth, the peoples of this barren and desolate world struggle to survive. Driven by animal instinct they compete against the harsh conditions, their giant predators, and warring tribes. When two people from opposing clans fall in love, existing conventions are shattered forever as each tribe struggles for supremacy and Man embarks on his tortuous voyage of civilization.