In 1936, Wu Chien-Shiung boards ocean liner President Hoover in Shanghai for California. She is 24-years-old, she is headed to America to study physics, and promises to return to her family in China soon. Over the next four decades, WWII and the Chinese Civil War will take this promise from her. She will become Dr. Wu, the first and only Chinese woman to work on the Manhattan Project and atomic bombs. She will marry and naturalise as an American citizen, and by the time she returns home, all her family will be dead. The Conservation of Parity tells the story of Wu's first decade in America, and how her determination to aid China turned her into one of the most instrumental physicists in American history. It is a story filled with science and history, but at its core, it is the journey of a woman who comes to America and continually tries to find her way back home.