Pour One for the Devil — Theodore C. Van Alst Jr.

When Dr. Van Vierlans receives an invitation from Mrs. Elizabeth Morgenstern to give a lecture at her island mansion off the coast of South Carolina, he doesn't think twice. There's a generous honorarium, and he relishes the chance to revisit the Sea Islands, where he once studied the Gullah language. 

The lavish house he arrives at is strangely out of time. No other historians appear, nor does an audience, as he passes the time chatting in Gullah with the household servants. Just when his suspicions become difficult to ignore, Mrs. Morgenstern plies him with a sumptuous feast that distracts him from her true motivesâ€"which may prove more sinister than anything he's prepared to imagine.