This mystery stars John Dickson Carr's gargantuan, shovel-hatted detective, Dr. Gideon Fell and takes place in England between the world wars. All of the characters act suspiciously, including the true and false heir to the extensive Farnleigh estate (and the title that goes with it), their two lawyers, the butler, Lady Farnleigh, and assorted family friends. The reader has many reasons to suspect each character in turn after the murder (or was it suicide?) of one of the two competing heirs. The only person who might be able to tell whether the true John Farnleigh died or still lives is his tutor, Murray who happens to have taken a thumb-o-graph of young John before he was sent away to America to live with a distant relative.
John wasn't the heir, but the black sheep of the family when he was packed off to Colorado via the spanking, new ocean liner, 'Titanic.' He was thought to have died when his ship sank on her maiden voyage, but after his older brother dies without issue, not one but two John Farnleighs show up within a year of each other to claim the family estate and title. The first one to appear marries John's childhood sweetheart and settles down to manage Farnleigh.
Then up pops John Farnleigh #2, one of the competing heirs dies, and someone steals Murray's thumb-o-graph. The reader is beset with conflicting stories and clues, when Dr. Fell finally lumbers onto the scene with his shovel-hat, swirling cape, and crutch-headed cane. He figures out who killed whom right away, but the reader is left grasping at hints (some of them pretty darn subtle - I think Carr cheats a little on this mystery) until the final denouement, which involves that fateful night when the 'Titanic' went down.
As always with this author, the eerie, suffocating atmosphere surrounding a mysterious death is tinged with an aura of the supernatural. "The Crooked Hinge" features devil worship and a horrible old eighteenth-century automaton called, 'The Golden Hag.' Her sinister appearances alone make this a novel worth savoring, and Carr also provides a meticulously plotted mystery.