Love at War begins halfway through World War Two when Anna Christensen has almost completed her business training. The daughter of a handsome Norwegian seafarer and his beautiful wife, Anna's looks attract much attention, especially from two army officers. Charismatic Captain Charles Milburn and his aide, 2nd Lieutenant Geoffrey Chandler are both attracted to the depot's new shorthand-typist, but it is Charles, although engaged to be married, who Anna finds irresistible.

The seaside town of Barry avoids the ruthless bombing affecting South Wales's cities and Charles revels in his comparatively 'cushy' number. Out of office hours, he's playing tennis, pursuing lady friends, and arranging a morale-boosting dance. After he is injured in a nightclub bombing, Anna and Geoffrey become closer, yet after Charles recovers, he makes a move on Anna.