Seven months ago Edda was on the World War I front lines as one of two hundred “Hello Girls,” female switchboard operators employed by the US Army. She spent her nights memorizing secret connection codes to stay ahead of spying enemies and her days connecting calls between platoons and bases and generals, all trying to survive—and win—a brutal war. Their lives were in Edda’s hands, and one day, in fateful seconds, everything went wrong.

Now Edda is back in Washington, D.C., working as an American Bell Telephone operator, the picture of respectability. But when her shift ends, she is barely hanging on, desperate to forget the circumstances that cut her time overseas short. When Edda receives a panicked phone call from someone who utters the fateful code word “Brightwood,” she has no choice but to confront her past.