Natacha Calestrémé began her career as a journalist. While collecting articles on the environment and wildlife, she realized that the courage of a handful of men and women was what stood between some species and extinction. She decided to find these people, tell the world about them, and in this way help them and the animals they were trying to save.

In 1999, ten years after her revelation, she found a producer, Thierry Berrod, who fell in love with her project. Since 2000, Natacha Calestrémé has been traveling all around the world to film documentaries on these heroes of nature: Paul Watson, who fights against whale hunters; Biruté Galdikas who has struggled for thirty years to protect orangoutangs, Hans Klingel, the famous zoologist and protector of the hippopotames; John Wamsley, the inventor of eco-tourism; and Olivier Behra, lemur-lover.