The story unfolds in China, where Katrin's marriage to busy M.D. Walter Fane is in trouble. Lonely and neglected, Katrin falls in love with diplomatic attaché Jack Townsend. When Walter discovers the affair, he takes Katrin inland to fight a cholera epidemic, maliciously thinking the disease will kill them both. But working together helps rebuild their marriage, until Townsend resurfaces. Now Katrin must choose.