First published in 1917, âThe Terrorâ is a short novel by Welsh author Arthur Machan set in England during the First World War. After an inexplicable series of murders are committed with no clue as to the perpetrator, a mystery starts to unravel in front of the townspeople. A gripping murder mystery by a modern master of the genre, âThe Terrorâ is not to be missed by those with a love of the uncanny and unexplained.