A domineering money-bags' suppressed incestuous urges go into overdrive when her half-brother brings a new bride home to the family’s gloomy Fifth Avenue mansion. The title refers to a secret soundproofed chamber that the villainess uses to entrap her enemies.
“The play that made Broadway Gasp!” This is a gripping melodrama, anchored by a fearsome performance by Morris as a controlling, maniacal mother to Taylor, determined to sabotage his marriage to winsome Venable. It was to be her only film appearance, although she had a fruitful stage career. Her simpering servant is played by Revere, in her debut, as a woman who is the constant victim of her mistress’ cruelty, who suffers in silence. The two males, Taylor and doctor Tapley, who offers solace to Venable, are both rather wet but offer her stolid support. The picture builds tension as Morris enacts her plan to cut Venable from her boy’s life until a stunning climax and a ghastly cackle bring it to a close. Mostly set in one room but this does not distract or weaken the strength of the situation and the rivetting Morris dominates it all.