Gerry Kennedy tells the story of sibling American radicals Joan and William Hinton.
Born into a progressive, intellectual Vermont family, Joan became the only female scientist to work on American experiments for the first atomic bomb. Horrified by the devastation of Hiroshima and Nagasaki, she began campaigning for civilian control of atomic energy.
In 1948, she and William turned their backs on the postwar American dream in order to savour revolution in China. Now 85, she still manages a dairy farm near Beijing.