London 1940. After her fiancé breaks off their engagement Evelyn decides to do her part for the war effort by signing up for construction work on Waterloo Bridge. Grieving after her little boy dies in an air raid Gwen is completely lost when her husband sends their younger children to the countryside for safety. Enlisting as a construction worker she is partnered with cheerful Evelyn. The two women strike up a heartwarming friendship. Musical prodigy Joan's life has always been dictated by her controlling mother. When an affair nearly ends in scandal Joan finally takes her life into her own hands. She soon finds work at Waterloo Bridge. Yet there are other troubles for her to overcome…