In February 2018, the Vatican recognised the 70th miracle of Lourdes. These miracles now attract 6 million people each year to the famous cave, the third largest Catholic pilgrimage site in the world. Of all these visitors, 60,000 are sick or disabled and hope to experience what is known as a “spontaneous cure”: there are about 7,300 cases to date. Following in the footsteps of Bernadette Soubirous, who at the age of 14 witnessed an apparition of the Virgin Mary, this documentary attempts to compare, analyse and unravel the mysteries surrounding these phenomena, which have existed for more than 160 years, from a historical and scientific point of view.