England, 1916. Independent-minded Bess Crawford's upbringing is far different from that of the usual upper-middle-class British gentlewoman. Growing up in India, she learned the importance of responsibility, honor, and duty from her offi­cer father. At the outbreak of World War I, she followed in his footsteps and volunteered for the nursing corps, serving from the battlefields of France to the doomed hospital ship Britannic.

On one voyage, Bess grows fond of the young, gravely wounded Lieutenant Arthur Graham. Something rests heavily on his conscience, and to give him a little peace as he dies, she promises to deliver a message to his brother. It is some months before she can carry out this duty, and when she's next in England, she herself is recovering from a wound.

When Bess arrives at the Graham house in Kent, Jonathan Graham listens to his brother's last wishes with surprising indifference. Neither his mother nor his brother Timothy seems to think it has any significance. Unsettled by this, Bess is about to take her leave when sudden tragedy envelops her. She quickly discovers that fulfilling this duty to the dead has thrust her into a maelstrom of intrigue and murder that will endanger her own life and test her courage as not even war has.