A visiting brother comes looking for answers about his sister's death and instead finds a castle full of torture devices, a husband unraveling before his eyes, and a secret that will not stay buried in its crypt.

THE PIT AND THE PENDULUM (1961) stars Vincent Price as Nicholas Medina, a Spanish nobleman tormented by the death of his wife Elizabeth, played by Barbara Steele. John Kerr is Francis Barnard, her brother, who arrives at the Medina castle demanding to know what happened to her and uncovers a history of madness and inherited cruelty reaching back to the Spanish Inquisition.

Richard Matheson wrote the screenplay, borrowing only the title and the central image of Edgar Allan Poe's story and inventing a full plot of guilt, grief, and revenge around it. Roger Corman directed on a modest budget for American International Pictures, using Floyd Crosby's cinematography and Daniel Haller's sets to stretch limited means into something lavish and strange.

This was the second entry in Corman's cycle of Poe adaptations starring Price, following House of Usher, with lurid color, a crumbling family estate, and Price delivering a performance that moves from wounded sorrow into total derangement.

The final sequence, about the swinging blade of the title, remains one of the defining images of American horror in the period.