Every mobile phone contains coltan, the mineral that makes capacitors work, and much of the world's supply comes from the Democratic Republic of Congo. The film follows the mineral from hand-dug pits in the eastern Congo, where militias control mines and tax the ore moving out, through smuggling routes across the border into Rwanda, and on into the supply chains of the electronics industry. Interviews with miners, traders, and armed fighters lay out how profits from coltan sales fund the conflict that has killed millions in the region, while footage inside mining camps shows the manual, dangerous conditions under which the ore is extracted, often by children. The film traces the paper trail that lets manufacturers claim ignorance about where their raw materials originate, and confronts the gap between a consumer product marketed as sleek and modern and the war economy sitting underneath it. The phone in your pocket, the film argues, is also a Congolese war's unlisted investor.