The villages in Congo, Burundi, and Tanzania that ring Lake Tanganyika are extremely isolated, which is apparent when Chicago doctor Amy Lehman lifts her shirt, turns around, and reveals a tattoo of the lake’s convoluted, rocky coast on her back. Delivering health care to these remote communities has become her passion. For now she rents local boats to deliver bed nets along the lake, where malaria is a leading cause of death. But her goal is to equip a floating hospital, which will bring medical care to some 3 million people. Although she trained as a cardiothoracic surgeon, childhood nerve damage prevented her from practicing. “I love chest surgery. No joke,” she says. “When I think about what else I could do that would keep me as compelled, it’s this.” So she presses ahead on plans for the Lake Tanganyika Floating Health Clinic, raising funds, commissioning a local shipbuilder, cajoling officials. “She’ll die getting this done,” says Damien Drake, who is collaborating with Fisher Stevens on a documentary film about Lehman.