Twelve unexplained phenomena with no apparent earthly explanation . . .
A dog-shaped gunpowder mark; an omen from the other side; a haunted house; a chilling seance; a case of split personalities; a recurring nightmare; an eerie wireless message; an elderly lady's hold over a young man; a disembodied cry of murder; a young man's sudden amnesia; a levitation experience; a mysterious SOS.
To discover the answers, delve into the supernatural storytelling of Agatha Christie.