Alberto, a young Portuguese man with monarchist ideas, is in exile in Belém do Pará in 1912. There he is employed by Velasco, a Spanish foreman, to work in Juca Tristao, a rubber plantation in the heart of the Amazon. After a long journey down the River Amazon under subhuman conditions he arrives at the Paraiso rubber plantation where he is put to work collecting rubber in the middle of the jungle under the protection of the Firmino. Alberto discovers a world which is strange and wild for him, in which the Indians, fever and the madness of men are everyday dangers. But he also finds friendship, loyalty and the solidarity of the rubber plantation workers against the despotic power of their exploiters.