Set in April 1942, Under Fire tells the story of Ruth Brown whose missing sister Jane is declared dead. Convinced her sister is still alive, Ruth follows clues from their small New Hampshire town to war-torn London trying to find her. Discovering that Jane has been murdered results in a faith crisis for Ruth, and she decides she must find Jane's killer. With the help of a German resistance member, Ruth catches the culprit and renews her relationship with God.