After feigning her own death in Cornwall to escape from Moriarty's perilous attention, Charlotte Holmes goes into hiding. But then she receives a tempting offer: Find a dossier the crown is desperately seeking, and she might be able to go back to a normal life. Her search leads her aboard the RMS Provence. In this eighth outing, in the midst of a terrifying storm in the Bay of Biscay, a murder takes place on the ship, and for once Charlotte must take care not to be embroiled in the investigation.