A trip on board the Oswaldo Cruz, cruising the Amazon to bring medical aid to the most remote villages. The Brazilian warship Oswaldo Cruz is on a peaceful mission. Its holds are crammed with medical equipment : a pile of drugs, bandages, dentist's chairs, even a mobile operating theatre. On board the hospital ship are three young doctors. They have decided to spend a year providing medical assistance to remote villages in Amazonia. They know that, as well as health care, their work will also consist of educating the villagers on hygiene and nutrition. Every time, before they set out, a detailed plan of action is drawn up. Over the four weeks of the next campaign, the doctors will visit more than fifty villages... if they can find them!