This film narrates the exploration carried out by an Italian expedition to Tegguidam Tessoum Oasis, in Niger. In this oasis, called salt oasis - using a source of salt water (the water is mixed with the sand; then they let it evaporate in a volcanic crater) it's produced the mineral salt, essential for men and animals. Then, long caravans take the salt from Tegguidam Tessoum to the far away African villages.