Christmas 1900. Victor Narraway, Thomas Pitt's former boss and his new wife Vespasia are travelling by train from Jaffa to Jerusalem. Although enjoying their time together and the interesting people they meet, Vespasia soon becomes concerned that someone is watching their every move. When one of their new acquaintances is found murdered, the only clue is a mysterious piece of parchment written in a foreign tongue, and a message imploring Narraway to continue the stranger's quest.