Edda, 18, has recently returned from working as a Hello Girl for the American Expeditionary Forces on the front lines of WWI. Now a telephone operator for Bell Systems in Washington, D.C., Edda (white) is weighted with guilt over an incident during her service: Despite her ability to quickly translate between French and English, and working hard to memorize codes that changed daily, she forgot a code word (“Brightwood”) at a critical moment, and 34 soldiers died as a result. Already depressed, Edda starts receiving haunting, accusatory calls while at work warning that she must tell the truth about what happened overseas. She’s determined to discover who’s behind them. With the help of Theo, a young man who also lives at her aunt’s boarding house, Edda begins investigating who might be behind the calls, starting with members of the dead soldiers’ families in the D.C. area. Her research adds layers of complexity to her feelings of guilt over their deaths, and to her feelings about Theo, who she discovers has a secret of his own. When Edda finally acknowledges details of the night she forgot the code word–she made the mistake just after being sexually assaulted by the officer who had been mentoring her—it gives her insight into the calls and the fact that her guilt is misplaced. This compelling historical mystery addresses PTSD, sexism, and sexual assault in ways relatable for contemporary readers while feeling authentic for the time. (Ages 12 and older)