Antal Szerb (1901–1945) was an essayist, novelist, playwright, and a formidable scholar whose books include History of Hungarian Literature, Journey by Moonlight, Oliver VII, and The Queen's Necklace. He was twice awarded the Baumgarten Prize, and in 1933 he was elected president of the Hungarian Literary Academy. Len Rix also translated Journey by Moonlight and Oliver VII.

At an end-of-London-season soiree, the young Hungarian scholar-dilettante Janos Batky is introduced to the Earl of Gwynedd, a reclusive eccentric who is the subject of strange rumors. Invited to the family seat--Pendragon Castle in North Wales--Batky receives a mysterious phone call warning him not to go; but he does and finds himself in a bizarre world of mysticism and romance, animal experimentation, and planned murder. His quest to solve the central mystery takes him down strange byways--old libraries and warehouse cellars, Welsh mountains, and underground tombs.