London, 1934. Clever young civil servant Doreen Bates is working in the same office as E, an older married man. In the years just before the war, they strike up a passionate affair. Doreen records it all with startling candor in her diary—secret midnight walks, countryside escapades, and stolen moments of intimacy. But, despite all the taboos of the time, and against his wishes, she is determined to have a child with E—even though she knows that her decision will provoke anger and shame from her family, friends, and colleagues. Eventually she gets pregnant and is amazed when twins are born during the war. However, Doreen faces an uncertain future—will E ever leave his wife and join his new family?