This hermetically sealed house mystery has a twist. The murders take place in a large manse atop “Arrow Mountain,” cut off from the world by a raging forest fire climbing the mountain, out of control, soon to devour the house and its inhabitants. Ellery’s explication takes place in the basement, as the house crumbles above them, and smoke tries to seep in under the door and through the windows. Will he solve the mystery before he and the suspects burn alive? “‘So,’ said Ellery with a ferocious scowl, ‘I propose as the last act of my worthless life to do that very thing.’
The story can be read as an act of desperation by two burned-out writers. They had just killed off detective Drury Lane, launched a monthly magazine, and were coming off a marathon run of eight published novels over two years. The fire approaching the mountain could have been a metaphor for their lives at the time. A mad scientist, “freaks,” and murder mixed with impending doom all make for a sensationalistic novel, hitting several plot elements designed to increase sales, or included because the cousins could not come up with anything more subtle.
The story can be read as a strange indictment on marriage: the Xaviers have isolated themselves from the world, in this house on a secluded mountain top, yet Mrs Xavier remains violently jealous, believing her husband is interested in entering sexual relations with every other women who enters their lives. Even her own wedding ring is not enough: she steals and hoards rings from whoever she can pry them from, even rings worn by men. She needs to possess all rings. For his part, Dr. Xavier specializes in studying conjoined people and animals, or, as they said in the olden days, “Siamese Twins,” in hopes of finding a way to separate the “two” bodies. So, she tries to keep them together, he looks for ways to separate.
The subtext is not the only new thing for the cousins in this book. This is also the first Ellery Queen novel with a “dying clue ,” or a hint left by the victim identifying the murderer. (The Tragedy of X also had a dying clue, but let’s just call that a Drury Lane mystery…) The thing is, though, that the dying clues in Siamese Twin Mystery are left, seemingly, by everyone but the victim. To quote Ellery himself:
“The ‘clues’ left in the dead hands…After a while I came to see that they were impossible. They were much too subtle to have emanated from the thoughts of a dying man. Too subtle and too complicated. Their very subtlety is what made their use by the murderer stupid. They flew in the face of the normal.”