Thirteen-year-old Ben Tracey is looking forward to spending the summer in the Democratic Republic of Congo, where his father has been hired to examine the valuable mineral Coltan that's being mined there. They soon realise that the people living in the village near the mine are frightened and it doesn't take long for Ben and his father to discover why: behind the door of every hut there is at least one person dying or seriously ill, and no one seems to be doing anything to help.