When Paul Bannerman, an ecologist in Africa, is diagnosed with cancer and prescribed treatment that makes him radioactive, his suddenly fragile existence makes him question his life for the first time. He is especially struck by the contradiction in values of his work as a conservationist and that of his wife, an advertising agency executive. Then when Paul moves in with his parents to protect his wife and young son from radiation, the strange nature of his condition leads his mother to face her own past.