The killer is revealed: not Hornbeck, but Finch’s own assistant, a meek woman named Mary Whittaker. Mary was also a test subject. Finch had secretly recorded her private confessions — including one about a past abortion (illegal and scandalous in 1908) — as part of his “lossless” experiments, claiming he could preserve human emotion in audio. Mary, terrified of eternal exposure, killed him in a panic and tried to erase the cylinder, not realizing the “click” was her own act being recorded.
The episode opens with a celebration at the Ogden residence. Arthur Conan Doyle (guest star) has returned to Toronto, this time not as a detective but as a spiritualist fascinated by the idea of capturing voices of the dead. He brings a gift for Dr. Julia Ogden: a new “lossless” wax cylinder recording device, engineered by a reclusive inventor named Ezra Finch. Unlike standard phonographs that degrade after a few plays, Finch’s cylinder uses a diamond stylus and a proprietary wax blend that promises “permanent, perfect sound — no loss of fidelity, even after a thousand repetitions.” murdoch mysteries season 12 lossless
Elara cracks the code. Using a modified oscilloscope, she translates the click’s subsonic harmonics into a visual waveform — and then into a crude but recognizable sound: the squeak of a specific floorboard in Finch’s lab, followed by the snap of a leather belt . The murder weapon, it turns out, was not a blunt object but a weighted strap from a piece of machinery — the very recording device’s drive belt, which Finch had reinforced with lead. The killer is revealed: not Hornbeck, but Finch’s
Murdoch returns home to Julia. She is sitting by the fire, the phonograph silent. She has decided not to play the lullaby again until the baby is born. “Some things are meant to be heard only once,” she says, placing a hand on her belly. Mary, terrified of eternal exposure, killed him in
In a dramatic scene, Murdoch plays the enhanced recording for Brackenreid and the suspect. Mary breaks down, confessing. “He said silence was just sound waiting to be heard. I wanted my silence to stay silent.”
Brackenreid scoffs. “A ghost in the grooves? We solve crimes with boots on the ground, not parlour tricks.”
The next morning, Ezra Finch is found dead in his laboratory — a locked room. The cause of death is blunt force trauma, but the weapon is missing. The only object in the room is a phonograph, its cylinder still turning. But when Murdoch plays it, he hears only silence punctuated by a single, sharp click.