In 229CE, Hadrian's Wall in Britannia, and the brave auxiliary soldiers who man it, provide the physical security for the northern frontier of the mighty Roman Empire. However, only an enlightened few understand the graver supernatural threats lurking amid the dark forests and trackless marshes of the border region - and in the hearts of men. Those enlightened few are yourselves, the Brotherhood of Mithras, who serve among the auxiliaries.The Prefect of your cohort has another mission for you, though thankfully this one seems less politically fraught than the last couple. Villagers from the Brigantes tribe south of the fort have reported an unusually poor harvest, followed by strange disappearances - and for some reason the Prefect seems to care enough to send you to investigate.

To swim the English Channel is regarded as an astounding feat of endurance — and no woman has yet managed it. The renowned American swimmer Gertie Eberhard plans to attempt the crossing in August 1926. She and her team are acutely aware that, of the two women known to have tried the journey before, one was never seen again and the other has mysteriously faded from public view. Eberhard has had Smythe's Discreet Investigations, London's first — indeed, only — all-female detective agency recommended to her, and has engaged the team to manage her security before and during the swim.