Perkoa, gold mine in Burkina Faso. Opio is 13 and has been working breaking rocks and dragging men and bags to the surface for several years. Every month he earns his living -a bag of stones extracted from the underground. To ensure a future for Opio, his father would like him to take a vocational training course but unfortunately he cannot afford the school fees. Opio will have to raise the money by himself and the only way to do so is to ask his boss for a promotion: the right to go down into the underground galleries that frighten him so much.