"I mark this day most especially with a White Stone."---Lewis Carroll, "The Diaries of Lewis Carroll" Edmund Whitty, a London newspaper correspondent who can usually be counted upon for crisp and lurid copy, has fallen upon lean times. After his triumphant expose of a notorious serial killer, he has inexplicably lost his knack for sensational reporting. Broke and desperate, he seizes upon a generous offer from a mysterious American to discredit a...